ISEE-3 Archives

November 15, 2016 by Fraser Cain

What Is The Interplanetary Transport Network?

It was with great fanfare that Elon Musk announced SpaceX’s plans to colonize Mars with the Interplanetary Transport System.

I really wish they’d stuck to their original name, the BFR, the Big Fabulous Rocket, or something like that.

The problem is that Interplanetary Transport System is way too close a name to another really cool idea, the Interplanetary Transport Network, which gives you an almost energy free way to travel across the entire Solar System. Assuming you’re not in any kind of rush.

When you imagine rockets blasting off for distant destinations, you probably envision pointing your rocket at your destination, firing the thrusters until you get there. Maybe turning around and slowing down again to land on the alien world. It’s how you might drive your car, or fly a plane to get from here to there.

But if you’ve played any Kerbal Space Program, you know that’s not how it works in space. Instead, it’s all about orbits and velocity. In order to get off planet Earth, you have be travelling about 8 km/s or 28,000 km/h sideways.

Artist's concept of a Bimodal Nuclear Thermal Rocket in Low Earth Orbit. Credit: NASA — Artist’s concept of a Bimodal Nuclear Thermal Rocket in Low Earth Orbit. Credit: NASA

So now, you’re orbiting the Earth, which is orbiting the Sun. If you want to get to Mars, you have raise your orbit so that it matches Mars. The absolute minimum energy needed to make that transfer is known as the Hohmann transfer orbit. To get to Mars, you need to fire your thrusters until you’re going about 11.3 km/s.

Then you escape the pull of Earth, follow a nice curved trajectory, and intercept the trajectory of Mars. Assuming you timed everything right, that means you intercept Mars and go into orbit, or land on its surface, or discover a portal to hell dug into a research station on Phobos.

If you want to expend more energy, go ahead, you’ll get there faster.

But it turns out there’s another way you can travel from planet to planet in the Solar System, using a fraction of the energy you would use with the traditional Hohmann transfer, and that’s using Lagrange points.

We did a whole article on Lagrange points, but here’s a quick refresher. The Lagrange points are places in the Solar System where the gravity between two objects balances out in five places. There are five Lagrange points relating to the Earth and the Sun, and there are five Lagrange points relating to the Earth and the Moon. And there are points between the Sun and Jupiter, etc.

Illustration of the Sun-Earth Lagrange Points. Credit: NASA

Three of these points are unstable. Imagine a boulder at the top of a mountain. It doesn’t take much energy to keep it in place, but it’s easy to knock it out of balance so it comes rolling down.

Now, imagine the whole Solar System with all these Lagrange points for all the objects gravitationally interacting with each other. As planets go around the Sun, these Lagrange points get close to each other and even overlap.

And if you time things right, you can ride along in one gravitationally balanced point, and the roll down the gravity hill into the grasp of a different planet. Hang out there for a little bit and then jump orbits to another planet.

In fact, you can use this technique to traverse the entire Solar System, from Mercury to Pluto and beyond, relying only on the interacting gravity of all these worlds to provide you with the velocity you need to make the journey.

Welcome to the Interplanetary Transport Network, or Interplanetary Superhighway.

Unlike a normal highway, though, the actual shape and direction these pathways take changes all the time, depending on the current configuration of the Solar System.

800px-Interplanetary_Superhighway — A stylized example of one of the many, ever-changing routes along the ITN. Credit: NASA

If you think this sounds like science fiction, you’ll be glad to hear that space agencies have already used a version of this network to get some serious science done.

NASA greatly extended the mission of the International Sun/Earth Explorer 3, using these low energy transfers, it was able to perform its primary mission and then investigate a couple of comets.

The Japanese Hiten spacecraft was supposed to travel to the Moon, but its rocket failed to get enough velocity to put it into the right orbit. Researchers at NASA’s Jet Propulsion Laboratory calculated a trajectory that used the Lagrange points to help it move slowly and get to the Moon any way.

NASA’s Genesis Mission used the technique to capture particles from the solar wind and bring them back to the Earth.

There have been other missions to use the technique, and missions have been proposed that might exploit this technique to fully explore all the moons of Jupiter or Saturn, for example. Traveling from moon to moon when the gravity points line up.

It all sounds too good to be true, so here’s the downside. It’s slow. Really, painfully slow.

Like it can take years and even decades to move from world to world.

Imagine in the far future, there are space stations positioned at the major Lagrange points around the planets in the Solar System. Maybe they’re giant rotating space stations, like in 2001, or maybe they’re hollowed out asteroids or comets which have been maneuvered into place.

Exterior view of a Stanford torus. Bottom center is the non-rotating primary solar mirror, which reflects sunlight onto the angled ring of secondary mirrors around the hub. Painting by Donald E. Davis

They hang out at the Lagrange points using minimal fuel for station keeping. If you want to travel from one planet to another, you dock your spacecraft at the space station, refuel, and then wait for one of these low-energy trajectories to open up.

Then you just kick away from the Lagrange point, fall into the gravity well of your destination, and you’re on your way.

In the far future, we could have space stations at all the Lagrange points, and slow ferries that move from world to world along low energy trajectories, bringing cargo from world to world. Or taking passengers who can’t afford the high velocity Hohmann transfer technique.

You could imagine the space stations equipped with powerful lasers that fill your ship’s solar sails with the photons it needs to take you to the next destination. But then, I’m a sailor, so maybe I’m overly romanticizing it.

Here’s another, even more mind-bending concept. Astronomers have observed these networks open up between interacting galaxies. Want to transfer from the Milky Way to Andromeda? Just get your spacecraft to the galactic Lagrange point in a few billion years as they pass through each other. With very little energy, you’ll be able to join the cool kids in Andromeda.

I love this idea that colonizing and traveling across the Solar System doesn’t actually need to take enormous amounts of energy. If you’re patient, you can just ride the gravitational currents from world to world. This might be one of the greatest gifts the Solar System has made available to us.

August 10, 2014April 26, 2016 by Tim Reyes

ISEE-3 Completes Lunar Flyby, Begins a Citizen Science Program

An Illustration of the ISEE-3 trajectory around the Earth, Moon and Sun. (Credits: Google Creative Labs, Skycorp Inc., Space Exploration Engineering)

The journey began on August 12, 1978 from Cape Canaveral on a Delta II launch vehicle. Now after 36 years and 30 billions miles of travel around the Sun — as well as a crowd-funded reboot of the spacecraft and a foiled attempt to put it into Earth orbit — the ISEE-3 has completed a return visit to the Earth-Moon system.

The spacecraft made its closest approach to the Earth on August 9 and flyby of the Moon, August 10, 2014. Closest approach was 15,600 km (9693 miles) from the Moon’s surface. With the lunar flyby, Skycorp, Inc. of Mountain View, California, with help from Google Creative Labs, has announced a revised mission for ISEE-3 to deliver science to the public domain.

ISEE-3 has marked several important milestones and achievements for NASA over the five decades in which it has traveled and monitored the particles and fields between the Earth and the Sun. Its latest milestone – returning to Earth, was planned and refined over 30 years ago. However, with NASA no longer interested in recovering the spacecraft because of the limitations of its present budgets, its impending return would be with no fanfare, no commanding, no recovery into Earth orbit and no new mission. With the news that NASA could not afford a recovery, space enthusiasts began to talk. Retired and active aerospace engineers began to exchange ideas with avid HAM radio operators around the World. Finally, one group took charge. They revived the vintage spacecraft and has now designed a new mission for the it.

NASA illustration of the ISEE-3 swing by the Moon, 1982. On August 10, 2014, ISEE-3 will fly within 15,600 km (9693 miles) from the Moon's surface. — NASA illustration of the ISEE-3 fly by the Moon, 1982. On August 10, 2014, ISEE-3 will fly within 15,600 km (9693 miles) above the Moon’s surface.

Enter Dennis Wingo and Austin Epps of Skycorp, Inc. Residing in an abandoned McDonald’s drive-thru on Moffett Field in Mountain View, California, they began a journey in March to recover the spacecraft. First off, before any recovery attempt could be undertaken, it required original documentation, so Dennis with assistance from Keith Cowing began contacting original ISEE-3 engineers, calling, knocking on NASA doors and finally began signing NASA space act agreements to have the documents released into their possession. And what fascinating documents they were.

Written long before the internet, before the first personal computers and when computer punch cards and main frames were the means to program and command spacecraft, most of the ISEE-3 documents resided as printed documents only, on none other than paper, yellowing and old, doomed to eventually rot away in modest storage rooms. Some had been converted to the modern archive format, Adobe’s PDF file format. This was the beginning of revival of a working knowledge to command the spacecraft. It was very sketchy but in about 90 days, documents appeared, documents were scanned to PDFs, searched and the team prepared for the recovery attempt.

Key Personnel of the ISEE-3 Reboot Project. From left, Casey Harper, Cameron Woodman, Austin Epps, Jacob Gold, Balint Seeber, Keith Cowing, Denis Wingo, Marco Colleluori and Ken Zin. — Key personnel of the ISEE-3 Reboot Project. From left, Casey Harper, Cameron Woodman, Austin Epps, Jacob Gold, Balint Seeber, Keith Cowing, Dennis Wingo, Marco Colleluori and Ken Zin. (Photo credit, Google Creative Labs)

The team grew rapidly and as the Beatles song goes, Skycorp got by with a little help from their friends. Actually, a lot of help from their friends. First, there was a crowd funding effort. Thousands of individuals from around the globe contributed to a final crowd funding purse of about $160,000. This is in contrast to the $100 million or much more that is required to reach just the launch date of a NASA mission.

Next, the people that had been exchanging comments on blogs (e.g. Planetary blog post on ISEE-3) began making themselves available, no charge, providing decades of accrued experience in spacecraft design and operation and other very relevant expertise. There were original NASA engineers, Robert Farquhar and David Dunham, Warren Martin, Bobby Williams, and Craig Roberts. HAM radio operators appeared or were contacted from as far as England (AMSAT-UK), Germany(Bochum Obs.) and as nearby as the SETI Institute in Mountain View, California. All this expertise, working knowledge and capable hardware had to converge very rapidly. By the latter half of May, they were ready.

The operators of the venerable Arecibo Radio Telescope offered their expertise and its 1000 foot radio dish for communication purposes. And an absolutely critical solution was found to replace the lack of any existing transmitter that could communicate with the old 40 year old technology. NASA had retired and scrapped the original Deep Space Network equipment. So technology developed by Ettus Research Corp. of Santa Clara, California was identified as a possible replacement for the non-existent transmitter. Ettus proposed a combination of open source software called Gnu Radio configured to work with Ettus developed Universal Software Radio Peripheral (USRP) platforms as the solution. With the Skycorp team constructing the command sequences, Ettus engineers Balint Seeber and a former engineer John Marlsbury rigged the critical substitute for a hardware transmitter and with the expertise to modulate and demodulate a radio signal, a trip to Puerto Rico and the Arecibo dish was undertaken in May.

After two weeks of some waiting on hardware and trial and error, there was success. Two-way communication was achieved and ISEE-3 truly became ISEE-3 Reboot. Further hiccups unfolded by trial and error, learning to command and receive with still less than complete working knowledge. More NASA space act agreements were necessary to permit the access to achieve success. Finally, NASA provided time on the Deep Space Network, the famous Goldstone radio dish and others in the network, famous for communicating with Apollo missions and Voyagers at the edge of the Solar System. This provided further attempts at communication that helped to resolve and understand issues. Furthermore, a Bell Labs engineer, Phil Karn Jr. (KA9Q) volunteered his expertise in late night work sessions, to demodulate and decode the incoming radio signal, to convert analog signal into 1’s and 0’s. Phil provided crucial input and energy to the ISEE-3 Reboot at a key juncture.

The ultimate goal could now be attempted – command the spacecraft to fire its rocket engines to change its trajectory and become captured by the Earth’s gravitational field. Mike Loucks of Space Exploration Engineering and engineers of Applied Defense Solutions, Inc. worked quickly to provide trajectory information and revisions. Finally, commanding ISEE-3 to fire its rockets was attempted and then attempted again and again. Skycorp concluded that father time was what was truly in command of ISEE-3’s destiny. Thirty-six years in space had taken its toll and Skycorp engineers realized that the fuel tanks had lost pressure. They could command it in all necessary ways but the spacecraft could not squeeze the fuel out of the tanks.

Recovering from this disappointment, Skycorp has arrived at today with the help of the original engineers lead by Robert Farquhar of Goddard Space Flight Center, along with the thousands through crowd funding contributions and an incredible group of volunteers. And along the way, Google Creative Labs documented the adventure and created the compendium which was delivered to the public domain last week, A Spacecraft for All. This web site provides a graphic illustration of both the ISEE-3 timeline as well as its incredible journey to explore the Sun-Earth relationship, study two comets and then undertake a 30 year journey to return to Earth on August 10, 2014.

Using the radio telescope at Morehead State University, they will continue receiving the commanded telemetry stream from the remaining viable science instruments, process the data and present it to the public and to professional researchers alike for analysis. While ISEE-3 could not be recovered into an Earth orbit as Farquhar had hoped decades ago, it will continue its journey around the Sun and return to the vicinity of the Earth in 2029. How long telemetry from ISEE-3 can be received as it travels away from the Earth remains to be seen, and keeping in contact with it will be a challenge for its new operators in the months ahead.

Watch the video below about the project:

June 4, 2014December 23, 2015 by Nancy Atkinson

Contact With 36-Year Old Spacecraft Results in Dancing, Hugs. Now Comes Even Bigger Challenge

A graphic illustrating the ISEE-3 spacecraft's history. Courtesy Tim Reyes.

What is it like to make contact with a 36-year old dormant spacecraft?

“The intellectual side of you systematically goes through all the procedures but you really end up doing a happy dance when it actually works,” Keith Cowing told Universe Today. Cowing, most notably from NASA Watch.com, and businessman Dennis Wingo are leading a group of volunteer engineers that are attempting to reboot the International Sun-Earth Explorer (ISEE-3) spacecraft after it has traveled 25 billion kilometers around the Solar System the past 30 years.

Its initial mission launched in 1978 to study Earth’s magnetosphere, and the spacecraft was later repurposed to study two comets. Now, on its final leg of a 30-plus year journey and heading back to the vicinity of Earth, the crowdfunding effort ISEE-3 Reboot has been working to reactivate the hibernating spacecraft since NASA wasn’t able to provide any funds to do so.

More Details: No turning back, NASA ISEE-3 Spacecraft Returning to Earth after a 36 Year Journey

The team awakened the spacecraft by communicating from the Arecibo radio telescope in Puerto Rico, using a donated transmitter. While most of the team has been in Puerto Rico, Cowing is back at home in the US manning the surge of media attention this unusual mission has brought.

@ISEE3Reboot More #ISEE3 post-First Contact pictures, inc. Dana & Phil from AO. @_jmalsbury from afar (& @bistromath) pic.twitter.com/j3XxVcckqy

— Balint Seeber (@spenchdotnet) June 2, 2014

Those at Arecibo are now methodically going through all the systems, figuring out what the spacecraft can and can’t do.

“We did determine the spin rate of spacecraft is slightly below what it should be,” Cowing said, “but the point there is that we’re now understanding the telemetry that we’re getting and its coming back crystal clear.”

For you tech-minded folks, the team determined the spacecraft is spinning at 19.16 rpm. “The mission specification is 19.75 +/- 0.2 rpm. We have also learned that the spacecraft’s attitude relative to the ecliptic is 90.71 degrees – the specification is 90 +/- 1.5 degrees. In addition, we are now receiving information from the spacecraft’s magnetometer,” Cowing wrote in an update on the website.

The next task will be looking at the propulsion system and making sure they can actually fire the engines for a trajectory correction maneuver (TCM), currently targeted for June 17.

One thing this TCM will do is to make sure the spacecraft doesn’t hit the Moon. Initial interactions with the ISEE-3 from Arecibo showed the spacecraft was not where the JPL ephemeris predicted it was going to be.

“That’s a bit troublesome because if you look at the error bars, it could hit Moon, or even the Earth, which is not good,” Cowing said, adding that they’ve since been able to refine the trajectory and found the ephemeris was not off as much as initially thought, and so such an impact is quite unlikely.

“However, it’s not been totally ruled out, — as NASA would say it’s a not a non-zero chance,” Cowing said. “The fact that it was not where it was supposed to be shows there were changes in its position. But assuming we can fire the engines when we want to, it shouldn’t be a problem. As it stands now, if we didn’t do anything, the chance of it hitting the Moon is not zero. But it’s not that likely.”

But the fact that the predicted location of the spacecraft is only off by less than 30,000 km is actually pretty amazing.

Dennis Wingo wrote this on the team’s website:

Consider this, the spacecraft has completed almost 27 orbits of the sun since the last trajectory maneuver. That is 24.87 billion kilometers. They are off course by less than 30,000 km. I can’t even come up with an analogy to how darn good that is!! That is almost 1 part in ten million accuracy! We need to confirm this with a DSN ranging, but if this holds, the fuel needed to accomplish the trajectory change is only about 5.8 meters/sec, or less than 10% of what we thought last week!

We truly stand on the shoulders of steely eyed missile men giants..

Dennis Wingo and ISEE-3 Reboot engineers at Arecibo. Image courtesy ISEE-3 Reboot.

In 1982, NASA engineers at Goddard Space Flight Center, led by Robert Farquhar devised the maneuvers needed to send the spacecraft ISEE-3 out of the Earth-Moon system. It was renamed the International Cometary Explorer (ICE) to rendezvous with two comets – Giacobini-Zinner in 1985 and Comet Halley in 1986.

“Bob Farquhar and his team initially did it with pencils on the back of envelopes,” Cowing said, “so it is pretty amazing. And we’re really happy with the trajectory because we’ll need less fuel – we have 150 meters per second of fuel available, and we’ll only need about 6 meters per second of maneuvering, so that will give us a lot of margin to do the other things in terms of the final orbit, so we’re happy with that. But we have to fire the engines first before we pat ourselves on the back.”

And that’s where the biggest challenge of this amateur endeavor lies.

ISEE-3 Reboot Project mission patch. Image courtesy ISEE-3 Reboot.

“The biggest challenge will be getting the engines to fire,” Cowing said. “The party’s over if we can’t get it to do that. The rest will be gravy. So that’s what we’re focusing on now.”

After the June 17 TCM, the next big date is August 10, when the team will attempt to put the spacecraft in Earth orbit and then resume its original mission that began back in 1978 – all made possible by volunteers and crowdfunding.

We’ll keep you posted on this effort, but follow the ISEE-3 Reboot Twitter feed, which is updated frequently and immediately after anything happens with the spacecraft. Also, for more detailed updates, check out the SpaceCollege website.

May 13, 2014December 23, 2015 by Tim Reyes

Guest Post: No turning back, NASA ISEE-3 Spacecraft Returning to Earth after a 36 Year Journey

Editor’s note: This guest post was written by Tim Reyes, a former NASA software engineer and analyst who has supported development of orbital and lander missions to the planet Mars since 1992.

The International Sun-Earth Explorer spacecraft (ISEE-3) is phoning home and will be returning whether we are ready or not. Launched in 1978 to study Earth’s magnetosphere, the spacecraft was later repurposed to study two comets. Now, on its final leg of a 30-plus year journey to return to Earth, there’s a crowdfunding effort called ISEE-3 Reboot aimed at reactivating the hibernating spacecraft since NASA is not offering any funding to do so.

Interestingly, on May 14th, the spacecraft will be in conjunction with the planet Jupiter, passing only 2 arc minutes from the giant gas planet. While the spacecraft is not visible to the human eye or optical telescopes, Jupiter on the 14th marks the spot where ISEE-3 resides in our night sky.

ISEE-3 Jupiter conjunction on May 14, 2014. Graphic courtesy of Tim Reyes.

Here’s a bit of history on the program and this spacecraft in particular: The International Sun-Earth Explorers 1, 2 and 3 were the vanguard of what became an ongoing NASA program to monitor and understand the Sun-Earth relationship. ISEE-3 was part of a 3 spacecraft international effort to study the interaction of the Solar Wind with the Earth’s magnetosphere.

In 1982, NASA engineers at Goddard Space Flight Center, led by Robert Farquhar devised an unprecedented sequence of propulsion maneuvers including Earth and Moon gravitational assists to send the spacecraft ISEE-3 out of the Earth-Moon system. It was rechristened as the International Cometary Explorer (ICE) to rendezvous with two comets – Giacobini-Zinner in 1985 and Comet Halley in 1986.

The trajectory given ISEE-3 to escape the Earth-Moon system and flyby comets included returning to Earth on August 10, 2014. Final tweaks to the trajectory were completed in 1987 to assure a flyby of the Moon which Farquhar knew could be used to return ISEE-3 to an Earth orbit.

Enter the 21st Century, 30 years later and documents and magnetic tapes have predictably disappeared. The software and hardware to program, command and transmit to ISEE-3 are long gone. An independent team of engineers, led by Dennis Wingo and Keith Cowing (the same leaders of the Lunar Orbiter Image Recovery Project (LOIRP) — recovering old imagery on magnetic tape reels from the first lunar orbiter missions), operating outside the ranks and hallways of NASA are now racing against the clock to accomplish a landmark achievement: to turn on, command and maneuver a NASA spacecraft long ago abandoned, its primary missions completed in the 1980s. There are no funds, no remaining hardware or mission software to execute but this is the 21st century.

As of this writing there are five days left to contribute to this project, which is at 92% of its goal.

“ISEE-3 Reboot” team leader Dennis Wingo, says that if the efforts to contact the spacecraft are successful, plans are to return the spacecraft to the Sun-Earth L1 Point. Wingo emphasizes that Farquhar remains as instrumental to the spacecraft’s recovery today as he was to its departure, providing critical insight into the spacecraft systems.

While ISEE-3 has been on its long journey to return to Earth, remarkable technological and social events have unfolded. The personal computer arrived and matured; visionaries such as Steve Jobs have come and gone. With the Internet — non-existent when ISEE-3 launched – now a RocketHub crowdfunding effort was started to raise funds. Teleconferencing, more limited to board rooms in the days ISEE-3’s launch-date have brought retired NASA engineers and Wingo’s band of engineers together.

Amateur radio operators now have technology sufficient to acquire the signal and through the internet are also a part of the recovery effort. These events have conspired to give the band of engineers a small window of opportunity to recover the spacecraft. Additionally, without the original hardware transmitter, today’s high-speed electronics are able to emulate in software the hardware from 36 years ago.

While budget woes and shortfalls have plagued NASA since the 1960s, the 1980s were especially difficult. Recall that it included a decade void of any missions to Mars. Additionally, Congress refused to fund a US led mission to flyby Comet Halley. NASA was left out in the comet’s return while European, the Soviets and Japanese all had spacecraft planned. Repurposing ISEE-3 filled this gap and it became the first spacecraft to ever fly through the tail of a comet.

Now 36 years after launch, a spacecraft that time forgot, ISEE-3 has become a time traveler. It is the twin astronaut returning home from his long journey to find his twin, now aged and the World transformed. Wingo and his engineers, by recovering ISEE-3 create a link from the past to the present new generations of engineers. Wingo’s Skycorp will make ISEE-3 scientific data open to the public and to researchers and present a system for training engineers in mission management and spacecraft systems.