[meteorite-list] 35-Year Old ICE Spacecraft Is Approaching Earth in 2014

[Ron Baalke]

http://www.planetary.org/blogs/emily-lakdawalla/2013/09181511-ice-is-returning-to-earth.html

ICE is returning to Earth; but do we have the will to regain control?
By Emily Lakdawalla
Planetary Society Blog
September 18, 2013

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-Moon libration 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.

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:

http://www.youtube.com/watch?feature=player_embedded&v=t2YRxdpjce0

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.