The Hubble Space Telescope has gone through its share of gyroscopes in its 34-year history in space. Astronauts replaced the gyros during the last servicing mission in 2009, bringing it back up to six (three with three spares), but they only last so long. Last week, HST went into safe mode because one of the gyros experienced fluctuations in power. NASA paused the telescope’s science operations today to investigate the fluctuations and perhaps come up with a fix.
With this one gyro experiencing problems, only two of the gyros remain fully operational. HST works best with three gyros, and so engineers are working to understand the issue and hopefully figure out a way to fix it remotely. However, several years ago, engineers figured out a way to still conduct science operations with only a single gyro.
You think you know someone, then you see them in a slightly different way and BAM, they surprise you. I’m not talking about other people of course, I’m talking about a fabulous star that has been studied and imaged a gazillion times. Beta Pictoris has been revealed by many telescopes, even Hubble to be home to the most amazing disk. Enter James Webb Space Telescopd and WALLOP, with its increased sensitivty and instrumentation a new, exciting feature emerges.
In 1931, Indian-American physicist Subrahmanyan Chandrasekhar proposed a resolution to Einstein’s Theory of General Relativity that postulated the existence of black holes. By 1972, astronomers obtained the first conclusive evidence that these objects existed in our Universe. Observations of quasars and the center of the Milky Way also revealed that most massive galaxies have supermassive black holes (SMBHs) at their cores. Since then, the study of black holes has revealed that these objects vary in size and mass, ranging from micro black holes (MBHs) and intermediate black holes (IMBHs) to SMBHs.
Using astronomical simulations and a technique known as Gravitational Lensing, an international team of astrophysicists detected what could be the largest black hole ever observed. This ultramassive black hole (UMBH) has a mass roughly 30 billion times that of our Sun and is located near the center of the Abell 1201 galaxy cluster, roughly 2.7 billion light-years from Earth. This is the first time a black hole has been found using Gravitational Lensing, and it could enable studies that look farther into space to find black holes and deepen our understanding of their size and scale.
In the history of space exploration, a handful of missions have set new records for ruggedness and longevity. On Mars, the undisputed champion is the Opportunityrover, which was slated to run for 90 days but remained in operation for 15 years instead! In orbit around Mars, that honor goes to the 2001 Mars Odyssey, which is still operational 20 years after it arrived around the Red Planet.
In deep space, the title for the longest-running mission goes to theVoyager 1 probe, which has spent the past 44 years exploring the Solar System and what lies beyond. But in Earth orbit, the longevity prize goes to the Hubble Space Telescope(HST), which is once again fully operational after experiencing technical issues. With this latest restoration of operations, Hubble is well on its way to completing 32 years of service.
By 2027, the Nancy Grace Roman Space Telescope – or Roman Space Telescope (RST), for short – will take to space and build on the legacy of the venerable Hubble Space Telescope (HST). Combing a large primary mirror, a camera as sensitive as its predecessors, and next-generation surveying capabilities, Roman will have the power of “One-Hundred Hubbles.” It’s little wonder then why the telescope is named after Dr. Roman (1925 – 2018), NASA’s first Chief Astronomer and the “Mother of Hubble.”
As part of its journey towards realization, this next-generation space telescope recently passed a crucial milestone. This would be the all-important Mission Critical Design Review (CDR), signaling that all design and developmental engineering work is complete. With this milestone reached, the next-generation space telescope is now ready to move from the conceptual stage into the fabrication and assembly phase.
In 1990, the field of astronomy was forever changed with the launch of the Hubble Space Telescope. While it was not the first space observatory, its unprecedented resolution and versatility allowed for the deepest and most detailed images of the Universe ever taken. The latest image to be released by the mission features the spiral galaxy NGC 691, which was captured in amazing detail by Hubble’s Wide Field Camera 3 (WFC3).
In the mid-2020s, NASA’s next-generation Wide Field Infrared Survey Telescope (WFIRST) will take to space. With unprecedented resolution and advanced instruments, it will build on the foundation established by the venerableHubble Space Telescope – which celebrated its 30th anniversary this year! In anticipation of all it will accomplish, NASA decided that the WFIRST needs a proper name, one that honors its connection to Hubble.
This week, NASA announced that henceforth, the WFIRST mission will be known as the Nancy Grace Roman Space Telescope (or Roman Space Telescope for short) in honor of Dr. Nancy Grace Roman (who passed away in 2018). In addition to being NASA’s first Chief Astronomer, she was also a tireless educator and advocate for women in STEMs whose work paved the way for space telescopes – leading to her nickname “the mother of Hubble.”
KENNEDY SPACE CENTER, FL – Today marked the end of an era for NASA as the last of the agency’s next generation Tracking and Data Relay Satellites (TRDS) that transmit the critical science data and communications for the Hubble Space Telescope and human spaceflight missions to the International Space Station, successfully rocketed to orbit this morning, Fri. Aug 18 from the Florida Space Coast.
The spectacular liftoff of the strangely fish-like TDRS-M science relay comsat atop a United Launch Alliance Atlas V rocket occurred at 8:29 a.m. EDT a.m. (2:29 GMT) Aug. 18 from Space Launch Complex 41 at Cape Canaveral Air Force Station.
The weather cooperated with relatively thin but artistic clouds and low winds and offered spectators a spectacular launch show that will not forget.
NASA’s $408 million next generation Tracking and Data Relay Satellites (TRDS) looks like a giant alien fish or cocooned creature. But actually plays an unparalleled role in relaying critical science measurements, research data and tracking observations gathered by the International Space Station (ISS), Hubble and a plethora of Earth science missions.
“TDRS is a critical national asset have because of its importance to the space station and all of our science missions, primarily the Hubble Space Telescope and Earth science missions that use TDRS,” said Tim Dunn, NASA’s TDRS-M launch director.
TDRS-M will provide high-bandwidth communications to spacecraft in low-Earth orbit. The TDRS network enables continuous communication with the International Space Station, the Hubble Space Telescope, the Earth Observing System and other programs supporting human space flight, said satellite builder Boeing, the prime contractor for the mission.
TDRS-M is the last of three satellites to be launched in the third generation of TDRS satellites. It is also the final satellite built based on Boeing’s 601 spacecraft bus series.
NASA plans to switch to much higher capacity laser communications for the next generation of TDRS-like satellites and therefore opted to not build a fourth third generation satellite after TDRS-M.
“The TDRS fleet is a critical connection delivering science and human spaceflight data to those who can use it here on Earth,” said Dave Littmann, the TDRS project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“TDRS-M will expand the capabilities and extend the lifespan of the Space Network, allowing us to continue receiving and transmitting mission data well into the next decade.”
TDRS-M joins a constellation of 9 TDRS satellites already in orbit and ups the fleet to ten orbiting satellites.
The Atlas V rocket and Centaur upper stage delivered TDRS-M to its desired preliminary orbit.
“Trajectory analysis in. Injection accuracy was within 1% of prediction #TDRSM,” tweeted ULA CEO Torey Bruno.
Several hours after the launch ground controllers reported the satellite was in good health.
On tap now is a four month period or orbit checkout by prime contractor Boeing as well as a series of five significant orbit raising maneuvers from its initial orbit to Geostationary orbit over the Pacific Ocean.
“This TDRS-M milestone is another step forward in Boeing’s commitment to developing technologies to support future NASA near-Earth, moon, Mars and deep space missions – and to do so affordably, drawing on our 40-plus years of strong Boeing-NASA partnership,” said Enrico Attanasio, executive director, Department of Defense and Civil Programs, Boeing Satellite Systems.
Ground controllers will then move it to its final orbit over the Atlantic Ocean.
NASA plans to conduct additional tests before putting TDRS-M into service early next year over the Atlantic.
The importance of the TDRS constellation of satellites can’t be overstated.
Virtually all the communications relay capability involving human spaceflight, such as the ISS, resupply vehicles like the SpaceX cargo Dragon and Orbital ATK Cygnus and the soon to launch human space taxis like crew Dragon, Boeing Starliner and NASA’s Orion deep space crew capsule route their science results voice, data, command, telemetry and communications via the TDRS network of satellites.
The TDRS constellation enables both space to space and space to ground communications for virtually the entire orbital period.
The two stage Atlas V rocket stands 191 feet tall.
TDRS-M, spacecraft, which stands for Tracking and Data Relay Satellite – M is NASA’s new and advanced science data relay communications satellite that will transmit research measurements and analysis gathered by the astronaut crews and instruments flying abroad the International Space Station (ISS), Hubble Space Telescope and over 35 NASA Earth science missions including MMS, GPM, Aura, Aqua, Landsat, Jason 2 and 3 and more.
The TDRS constellation orbits 22,300 miles above Earth and provide near-constant communication links between the ground and the orbiting satellites.
TRDS-M will have S-, Ku- and Ka-band capabilities. Ka has the capability to transmit as much as six-gigabytes of data per minute. That’s the equivalent of downloading almost 14,000 songs per minute says NASA.
The TDRS program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
TDRS-M is the third satellite in the third series of NASA’s American’s most powerful and most advanced Tracking and Data Relay Satellites. It is designed to last for a 15 year orbital lifetime.
The first TDRS satellite was deployed from the Space Shuttle Challenger in 1983 as TDRS-A.
TDRS-M was built by prime contractor Boeing in El Segundo, California and is the third of a three satellite series – comprising TDRS -K, L, and M. They are based on the Boeing 601 series satellite bus and will be keep the TDRS satellite system operational through the 2020s.
TDSR-K and TDRS-L were launched in 2013 and 2014.
The Tracking and Data Relay Satellite project is managed at NASA’s Goddard Space Flight Center.
TDRS-M was built as a follow on and replacement satellite necessary to maintain and expand NASA’s Space Network, according to a NASA description.
The gigantic satellite is about as long as two school buses and measures 21 meters in length by 13.1 meters wide.
It has a dry mass of 1800 kg (4000 lbs) and a fueled mass of 3,454 kilogram (7,615 lb) at launch.
Watch for Ken’s continuing onsite TDRS-M, CRS-12, ORS 5 and NASA and space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
NASA GODDARD SPACE FLIGHT CENTER, MD – It’s Mesmerizing ! That’s the overwhelming feeling expressed among the fortunate few setting their own eyeballs on the newly exposed golden primary mirror at the heart of NASA’s mammoth James Webb Space Telescope (JWST) – a sentiment shared by the team building the one-of-its-kind observatory and myself during a visit this week by Universe Today.
“The telescope is cup up now [concave]. So you see it in all its glory!” said John Durning, Webb Telescope Deputy Project Manager, in an exclusive interview with Universe Today at NASA’s Goddard Space Flight Center on Tuesday, May 3, after the covers were carefully removed just days ago from all 18 primary mirror segments and the structure was temporarily pointed face up.
“The entire mirror system is checked out, integrated and the alignment has been checked.”
It’s a banner year for JWST at Goddard where the engineers and technicians are well into the final assembly and integration phase of the optical and science instrument portion of the colossal observatory that will revolutionize our understanding of the cosmos and our place it in. And they are moving along at a rapid pace.
JWST is the scientific successor to NASA’s 25 year old Hubble Space Telescope. It will become the biggest and most powerful space telescope ever built by humankind after it launches 30 months from now.
The flight structure for the backplane assembly truss that holds the mirrors and science instruments arrived at Goddard last August from Webb prime contractor Northrop Grumman Aerospace Systems in Redondo Beach, California.
The painstaking assembly work to piece together the 6.5 meter diameter primary mirror began just before the Thanksgiving 2015 holiday, when the first unit was successfully installed onto the central segment of the mirror holding backplane assembly.
Technicians from Goddard and Harris Corporation of Rochester, New York then methodically populated the backplane assembly one-by-one, sequentially installing the last primary mirror segment in February followed by the single secondary mirror at the top of the massive trio of mirror mount booms and the tertiary and steering mirrors inside the Aft Optics System (AOS).
Everything proceeded according to the meticulously choreographed schedule.
“The mirror installation went exceeding well,” Durning told Universe Today.
“We have maintained our schedule the entire time for installing all 18 primary mirror segments. Then the center section, which is the cone in the center, comprising the Aft Optics System (AOS). We installed that two months ago. It went exceedingly well.”
The flight structure and backplane assembly serve as the $8.6 Billion Webb telescopes backbone.
The next step is to install the observatory’s quartet of state-of-the-art research instruments, a package known as the ISIM (Integrated Science Instrument Module), in the truss structure over the next few weeks.
“The telescope is fully integrated and we are now doing the final touches to get prepared to accept the instrument pack which will start happening later this week,” Durning explained.
The integrated optical mirror system and ISIM form Webb’s optical train.
“So we are just now creating the new integration entity called OTIS – which is a combination of the OTE (Optical Telescope Assembly) and the ISIM (Integrated Science Instrument Module) together.”
“That’s essentially the entire optical train of the observatory!” Durning stated.
“It’s the critical photon path for the system. So we will have that integrated over the next few weeks.”
The combined OTIS entity of mirrors, science module and backplane truss weighs 8786 lbs (3940 kg) and measures 28’3” (8.6m) x 8”5” (2.6 m) x 7”10“ (2.4 m).
After OTIS is fully integrated, engineers and technicians will spend the rest of the year exposing it to environmental testing, adding the thermal blanketry and testing the optical train – before shipping the huge structure to NASA’s Johnson Space Center.
“Then we will send it to NASA’s Johnson Space Center (JSC) early next year to do some cryovac testing, and the post environmental test verification of the optical system,” During elaborated.
“In the meantime Northrup Grumman is finishing the fabrication of the sunshield and finishing the integration of the spacecraft components into their pieces.”
“Then late in 2017 is when the two pieces – the OTIS configuration and the sunshield configuration – come together for the first time as a full observatory. That happens at Northrup Grumman in Redondo Beach.”
Webb’s optical train is comprised of four different mirrors. We discussed the details of the mirrors, their installation, and testing.
“There are four mirror surfaces,” Durning said.
“We have the large primary mirror of 18 segments, the secondary mirror sitting on the tripod above it, and the center section looking like a pyramid structure [AOS] contains the tertiary mirror and the fine steering mirror.”
“The AOS comes as a complete package. That got inserted down the middle [of the primary mirror].”
Each of the 18 hexagonal-shaped primary mirror segments measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). They are made of beryllium, gold coated and about the size of a coffee table.
In space, the folded mirror structure will unfold into side by side sections and work together as one large 21.3-foot (6.5-meter) mirror, unprecedented in size and light gathering capability.
The lone rounded secondary mirror sits at the top of the tripod boom over the primary.
The tertiary mirror and fine steering mirror sit in the Aft Optics System (AOS), a cone shaped unit located at the center of the primary mirror.
“So how it works is the light from the primary mirror bounces up to the secondary, and the secondary bounces down to the tertiary,” Durning explained.
“And then the tertiary – which is within that AOS structure – bounces down to the steering mirror. And then that steering mirror steers the beams of photons to the pick off mirrors that sit below in the ISIM structure.”
“So the photons go through that AOS cone. There is a mask at the top that cuts off the path so we have a fixed shape of the beam coming through.”
“It’s the tertiary mirror that directs the photons to the fine steering mirror. The fine steering mirror then directs it [the photons] to the pick off mirrors that sit below in the ISIM structure.”
So the alignment between the AOS system and the telescopes primary and secondary mirrors is incredibly critical.
“The AOS tertiary mirror catches the light [from the secondary mirror] and directs the light to the steering mirror. The requirements for alignment were just what we needed. So that was excellent progress.”
“So the entire mirror system is checked out. The system has been integrated and the alignment has been checked.”
Webb’s golden mirror structure was tilted up for a very brief period this week on May 4 as seen in this NASA time-lapse video:
The 18-segment primary mirror of NASA’s James Webb Space Telescope was raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on May 4, 2016. Credit: NASA
The gargantuan observatory will significantly exceed the light gathering power of NASA’s Hubble Space Telescope (HST) – currently the most powerful space telescope ever sent to space.
With the mirror structure complete, the next step is ISIM science module installation.
To accomplish that, technicians carefully moved the Webb mirror structure this week into the clean room gantry structure.
As shown in this time-lapse video we created from Webbcam images, they tilted the structure vertically, flipped it around, lowered it back down horizontally and then transported it via an overhead crane into the work platform.
Time-lapse showing the uncovered 18-segment primary mirror of NASA’s James Webb Space Telescope being raised into vertical position, flipped and lowered upside down to horizontal position and then moved to processing gantry in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on May 4/5, 2016. Images: NASA Webbcam. Time-lapse by Ken Kremer/kenkremer.com/Alex Polimeni
The telescope will launch on an Ariane V booster from the Guiana Space Center in Kourou, French Guiana in 2018.
The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).
Webb is designed to look at the first light of the Universe and will be able to peer back in time to when the first stars and first galaxies were forming. It will also study the history of our universe and the formation of our solar system as well as other solar systems and exoplanets, some of which may be capable of supporting life on planets similar to Earth.
More about ISIM in the next story.
Watch this space for my ongoing reports on JWST mirrors, science, construction and testing.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Five time space shuttle astronaut and current NASA science chief John Grunsfeld – best known as the ‘Hubble Hugger’ for three critical and dramatic servicing and upgrade missions to the iconic Hubble Space Telescope – his decided to retire from the space agency he faithfully served since being selected as an astronaut in 1992.
“John Grunsfeld will retire from NASA April 30, capping nearly four decades of science and exploration with the agency. His tenure includes serving as astronaut, chief scientist, and head of NASA’s Earth and space science activities,” NASA announced.
Indeed, Grunsfeld was the last human to touch the telescope during the STS-125 servicing mission in 2009 when he served as lead spacewalker.
The STS-125 mission successfully upgraded the observatory to the apex of its scientific capability during five spacewalks by four astronauts and extended the life of the aging telescope for many years. Hubble remains fully operable to this day!
In April 2015, Hubble celebrated 25 years of operations, vastly outperforming its planned lifetime of 15 years.
“Hubble has given us 25 years of great service. Hopefully we’ll get another 5 to 10 years of unraveling the mysteries of the Universe,” Grunsfeld told me during a recent interview at NASA Goddard.
In his most recent assignment, Grunsfeld was NASA’s Science Chief working as the Associate Administrator for the Science Mission Directorate (SMD) at NASA Headquarters in Washington, D.C. since January 2012.
“John leaves an extraordinary legacy of success that will forever remain a part of our nation’s historic science and exploration achievements,” said NASA Administrator Charlie Bolden, in a statement.
“Widely known as the ‘Hubble Repairman,’ it was an honor to serve with him in the astronaut corps and watch him lead NASA’s science portfolio during a time of remarkable discovery. These are discoveries that have rewritten science textbooks and inspired the next generation of space explorers.”
Grunsfeld was inducted into the U.S. Astronaut Hall of Fame in 2015.
He received his PhD in physics in 1988 and conducted extensive research as an astronomer in the fields of x-ray and gamma ray astronomy and high-energy cosmic ray studies.
NASA said that Grunsfeld’s deputy Geoff Yoder will serve as SMD acting associate administrator until a successor is named.
“After exploring strange new worlds and seeking out new life in the universe, I can now boldly go where I’ve rarely gone before – home,” said Grunsfeld.
“I’m grateful to have had this extraordinary opportunity to lead NASA science, and know that the agency is well-positioned to make the next giant leaps in exploration and discovery.”
During his tenure as science chief leading NASA’s Science Mission Directorate Grunsfeld was responsible for managing over 100 NASA science missions including the Mars orbital and surface assets like the Curiosity and Opportunity Mars rovers, New Horizons at Pluto, MESSENGER, upcoming Mars 2020 rover and OSIRIS-Rex as well as Earth science missions like the Deep Space Climate Observatory, Orbiting Carbon Observatory-2, and Global Precipitation Measurement spacecraft -which resulted numerous groundbreaking science, findings and discoveries.
Dr. Grunsfeld is a veteran of five spaceflights: STS-67 (1995), STS-81 (1997), STS-103 (1999) STS-109 (2002) and STS-125 (2009), during which time he logged more than 58 days in space, including 58 hours and 30 minutes of EVA in 8 spacewalks.
He briefly retired from NASA in December 2009 to serve as Deputy Director of the Space Telescope Science Institute, in Baltimore, Maryland. He then returned to NASA in January 2012 to serve as SMD head for over four years until now.
From his NASA bio, here is a summary of John Grunsfeld’s space flight experience during five shuttle flights:
STS-67/Astro-2 Endeavour (March 2 to March 18, 1995) launched from Kennedy Space Center, Florida, and landed at Edwards Air Force Base, California. It was the second flight of the Astro observatory, a unique complement of three ultraviolet telescopes. During this record-setting 16-day mission, the crew conducted observations around the clock to study the far ultraviolet spectra of faint astronomical objects and the polarization of ultraviolet light coming from hot stars and distant galaxies. Mission duration was 399 hours and 9 minutes.
STS-81 Atlantis (January 12 to January 22, 1997) was a 10-day mission, the fifth to dock with Russia’s Space Station Mir and the second to exchange U.S. astronauts. The mission also carried the Spacehab double module, providing additional middeck locker space for secondary experiments. In 5 days of docked operations, more than 3 tons of food, water, experiment equipment and samples were moved back and forth between the two spacecraft. Grunsfeld served as the flight engineer on this flight. Following 160 orbits of the Earth, the STS-81 mission concluded with a landing on Kennedy Space Center’s Runway 33, ending a 3.9-million-mile journey. Mission duration was 244 hours and 56 minutes.
STS-103 Discovery (December 19 to December 27, 1999) was an 8-day mission, during which the crew successfully installed new gyroscopes and scientific instruments and upgraded systems on the Hubble Space Telescope (HST). Enhancing HST scientific capabilities required three spacewalks (EVAs). Grunsfeld performed two spacewalks, totaling 16 hours and 23 minutes. The STS-103 mission was accomplished in 120 Earth orbits, traveling 3.2 million miles in 191 hours and 11 minutes.
STS-109 Columbia (March 1 to March 12, 2002) was the fourth HST servicing mission. The crew of STS-109 successfully upgraded the HST, installing a new digital camera, a cooling system for the infrared camera, new solar arrays and a new power system. HST servicing and upgrades were accomplished by four crewmembers during a total of five EVAs in 5 consecutive days. As Payload Commander on STS-109, Grunsfeld was in charge of the spacewalking activities and the Hubble payload. He also performed three spacewalks totaling 21 hours and 9 minutes, including the installation of the new Power Control Unit. STS-109 orbited the Earth 165 times and covered 3.9 million miles in over 262 hours.
STS-125 Atlantis (May 11 to May 24, 2009) was the fifth and final Hubble servicing mission. After 19 years in orbit, the telescope received a major renovation that included the installation of a new wide-field camera, a new ultraviolet telescope, new batteries, a guidance sensor, gyroscopes and other repairs. Grunsfeld served as the lead spacewalker in charge of the spacewalking and Hubble activities. He performed three of the five spacewalks on this flight, totaling 20 hours and 58 minutes. For the first time while in orbit, two scientific instruments were surgically repaired in the telescope. The STS-125 mission was accomplished in 12 days, 21 hours, 37 minutes and 09 seconds, traveling 5,276,000 miles in 197 Earth orbits.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Learn more about Hubble, NASA Mars rovers, Orion, SLS, ISS, Orbital ATK, ULA, SpaceX, Boeing, Space Taxis, NASA missions and more at Ken’s upcoming outreach events:
Apr 9/10: “NASA and the Road to Mars Human Spaceflight programs” and “Curiosity explores Mars” at NEAF (NorthEast Astronomy and Space Forum), 9 AM to 5 PM, Suffern, NY, Rockland Community College and Rockland Astronomy Club – http://rocklandastronomy.com/neaf.html
Apr 12: Hosting Dr. Jim Green, NASA, Director Planetary Science, for a Planetary sciences talk about “Ceres, Pluto and Planet X” at Princeton University; 7:30 PM, Amateur Astronomers Assoc of Princeton, Peyton Hall, Princeton, NJ – http://www.princetonastronomy.org/
Apr 17: “NASA and the Road to Mars Human Spaceflight programs”- 1:30 PM at Washington Crossing State Park, Nature Center, Titusville, NJ – http://www.state.nj.us/dep/parksandforests/parks/washcros.html