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ICE is returning to Earth; but do we have the will to regain control?

Posted by Emily Lakdawalla

18-09-2013 17:37 CDT

Topics: mission status, comet Halley armada

In 1978, the International Sun-Earth Explorer (ISEE-3) spacecraft began its mission to study Earth's magnetosphere from a position at one of the Earth-Sun Lagrange points -- specifically, the L1 point, located between Earth and the Sun where the two bodies' gravity cancels. In 1983, ISEE-3 was renamed the International Cometary Explorer (ICE) and used the Moon's gravity to send it on to encounter comet Giacobini-Zinner, which it encountered in 1985. Later, ICE performed distant observations of comet Halley. Ever since then, it's been in solar orbit, traveling slightly faster than Earth. It has outdistanced us, traveling very close to 31 times around the Sun in the time that it has taken us to complete 30. And now it's approaching us from behind. It will make its closest approach again in August, 2014.

ICE swings past the Moon


ICE swings past the Moon
NASA's ISEE-3 spacecraft streaks just 116 km above the lunar surface December 22, 1983, as it is catapulted by the Moon's gravity toward a September 11, 1985, encounter with Comet Giacobini-Zinner.

Although out of contact for a long time, the Deep Space Network successfully communicated with it five years ago today, on September 18, 2008. That's the last time we've heard from it, but there's no particular reason to think it's not still functional; the 2008 contact happened after nine years of no communication.

When it comes back to Earth, it would be possible to recapture it into a halo orbit (that is, an orbit at the L1 point). But to do that, we'll have to reestablish regular communications with, and control of, the spacecraft. It won't be easy, but it's doable. But it will cost money, and given the current financial problems in Washington, it's unclear where that money will come from. Recognizing they have an uphill battle, ICE's supporters put together a video as well as a Facebook page:

ISEE-3 Returns

On August 10, 2014, ISEE-3/ICE (The International Sun-Earth Explorer-3/International Cometary Explorer) will return to the Earth-Moon system after 31 years. This historic spacecraft, launched in 1978, was the first to orbit the Sun-Earth L1 point (first Lagrangian Point) to study the solar wind. In 1983, after several close lunar flybys, it was sent off to become the first spacecraft to intercept a comet (Giacobini-Zinner). After the comet flyby, the spacecraft continued to drift farther from Earth in a solar orbit which brought it back again after about 3 decades. The return of ISEE-3/ICE provides an opportunity to train students in mission operations and, if it is healthy enough, could serve the science community once again.

It's ironic, really. ICE left Earth in the darkest days of NASA, and it is returning to Earth when NASA is experiencing its biggest crisis since. When it left in 1983, ICE was the last American spacecraft to depart Earth for deep space for six years, until Magellan in 1989. Since then, NASA has expanded across the solar system, but now it's contracting once more. Amid rumors that such great spacecraft as Cassini may see their missions end early for lack of funds, how can we afford spending even a little money on a mission as old as ICE?

There's nothing that I can do but be optimistic. I know others are working on the funding problem; let me tell you about the engineering problems, and the science we could achieve.

I got an email today from Leonard Garcia, one of several people at different institutions who are trying to figure out how to regain control of ICE and recapture it into halo orbit. "We have less than 11 months until Earth close approach and we need to make a trajectory correction maneuver several months before that," he wrote. They need to command its rockets to fire before June 2014. The sooner they do it, the less fuel it will cost. They have plenty -- 150 meters per second worth, more or less -- so as long as they regain control in time, they should have fuel to operate for a while.

A big question is whether we even still know how to communicate with the spacecraft. It was built in the 1970s, at the same time as the Voyagers. But we've been in continuous communication with the Voyagers since their launch; the same isn't true of ICE. So the first step is for a team at Goddard Space Flight Center to research that question. Can we figure out how to talk to ICE? What will those communications cost?

Once they've confirmed that communications are possible, the next thing we need to do is to assess the spacecraft's health, and the health of its instruments. It wouldn't be worth the effort if all the instruments were dead. There's no reason they should be -- most of the Voyager instruments are still working fine -- but we have to check.

What data could ICE send us? Garcia explained its utility in monitoring the solar wind: "There are currently a couple of spacecraft serving the science community in [the L1] region and they will be supplemented soon by the DSCOVR satellite. The plasma medium however, can be quite complex and an additional reference point will be of great value if it can be provided at a reasonable cost. As you noted in your 2008 blog about the initial contact with the spacecraft, ISEE-3/ICE has an impressive suite of scientific instruments on board well suited for this effort. "

But the question of whether it's all worth it comes down to cost. One interesting way that ICE advocates are talking about keeping costs low is to make spacecraft operation a student effort. In an article written for Space News, Daniel Baker explained: "At the University of Colorado at Boulder, for example, a space research institute — the Laboratory for Atmospheric and Space Physics (LASP) — has successfully operated numerous NASA space missions. The most recent example is the Kepler mission searching for Earth-like planets around other stars in our galaxy. By emphasizing students in the mission operations roles, LASP is able to carry out mission functions in an extraordinarily effective way. Moreover, the mission operation using students is a highly productive way to educate and train the next generation of young engineers, scientists and managers. It is proposed that the University of Colorado at Boulder work with a consortium of leading spacefaring universities in the United States to develop a program to command, control and scientifically operate the ISEE/ICE spacecraft."

One major challenge that Garcia mentioned to me is that ICE has no onboard data storage capability. That means it can only return data while in contact with a ground station, which means you need ground stations all over the world. Therein lies an opportunity, though: Baker says "There is every reason to believe that spacefaring partners in the international community would love to participate in the restored ISEE mission. For example, colleagues at the Russian Space Research Institute have expressed a strong desire to join the ISEE/ICE program. Through active involvement of academia in the U.S. and separately funded agencies abroad, it should be possible to revivify the ISEE/ICE spacecraft at a very low out-of-pocket cost. In doing so, U.S. taxpayers would be able to further recoup benefits of investments made some 40 years ago."

The clock is ticking. Orbital mechanics won't wait for us to get our financial act together.

See other posts from September 2013


Or read more blog entries about: mission status, comet Halley armada


Robspace54: 09/19/2013 07:42 CDT

Seems a shame to consider "throwing away" a working spacecraft, but that has happened before. I understand that the "ancient" comm protocols and gear must be refurbished. How much money to do that?

Douglas: 09/19/2013 10:39 CDT

I just hope this thing doesn't go all V'ger on us when we reestablish communications. Correction I do hope that happens.

Nicholas: 09/19/2013 09:13 CDT

Wait, was it sent to the Earth Moon L1, or the Sun Earth L1? The first paragraph is confusing.

Emily Lakdawalla: 09/20/2013 09:34 CDT

Sorry, I'd tried to fix that error yesterday, but a problem with the website prevented any changes to already published material for the last 24 hours. It's finally fixed now.

Bob: 09/20/2013 10:13 CDT

When ICE first left L1 it was "given" to the Smithsonian but I think they have money problems also.

LordJohn: 09/22/2013 04:11 CDT

Sadly, I am not really sure that the gains are enough to offset the cost and not inconsiderable effort. Having just "lost!" Deep Impact, a spacecraft we did have all the information abou and was on an extended mission, the efforts and resources might be best devoted to getting the most out of systems we know are working well. If we just want to track something old then Explorer 6 might still be live and it is heading towards 50 years old. If there was DSN network time, money and all free, thenwe can choose, but New Horizons, Voyager and Cassini and all the Mars and venus missions seem the most important to keep following.

bob: 09/23/2013 10:50 CDT

Even if the instruments still work it's doubtful if the Experimenters associated with them are alive!

Chris S: 09/24/2013 03:49 CDT

I'm curious about what happens to this craft if we do nothing at all. I'm recalling the sun-orbiting booster shell that was also considered to have caught up with Earth (designated 2010 KQ until it was determined to be artificial [1], now known as RK252A5[2]). Essentially, a faster, lower, solar orbit results in the craft catching up to Earth. When it enter's Earth's gravitational influence, it is pulled up, past Earth's orbit, into a slightly higher solar orbit -- hence slower, and falling behind Eartth. It then takes several decades for Earth to catch up with the craft. As Earth closes on the craft from behind, the process reverses - the craft is pulled down to a lower faster orbit again, and (slowly!) speeds away to catch up with Earth again. Is this an orbit that ICE might follow if we don't recapture it? [1: ] [2: ]

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