KISS: observing during cruise and after prime

The KISS is running a mini-workshop at KITP on doing Exoplanet Science Measurements from Solar System probes.

There are a bunch of spacecraft up there, with a lot of instruments.
Many of them, especially the solar system probes, spend a fair amount of time in a quiet cruise phase, where instruments are powered down or in passive mode.
Some missions also have a finite time prime mission, but the spacecraft continues to function and may take more observations.

There is considerable interest to make use of this capability, to use the spacecraft more efficiently, and to use the people more efficiently, and NASA has set up a Science Analysis Group, within a sub-committee of the Astrophysics Advisory Group, to explore current and future ideas for this.

The Kext Institute for Space Studies is sponsoring a 2 day mini-workshop at the Kavli Institute for Theoretical Physics, on potential Exoplanet observations, held during the ongoing Theory and Observations of Exoplanets program at KITP.


An example, the example, is the EPOXI extended mission using the Deep Impact spacecraft, before DI goes onto another comet in late 2010.
EPOXI got some data, but their experience reflects both the benefits and problems of attempting this.

Moon transiting Earth - from EPOXI - click through for videos

So, what is the catch...

Well, this is secondary science, so it must not interfere with the prime mission.
So scheduling is completely subservient to prime mission requirements, including delays and rescheduling; and, particularly during the pre-prime mission cruise phase, the secondary science must not jeopardize the mission, instruments or spacecraft.
So, there is a trade-off there between wanting to exercise the instruments and get calibrations etc, vs risking damage, for example to moving parts (reaction wheels, gyros etc), power systems (degradation, thermal cycling etc), and optics and electronics due to exposure or thermal cycling.
So post-prime mission observations can often be a better bet. Spacecraft can last a surprising long time, long past the prime mission, and on flybys, for example, there is no more opportunity for prime mission observations.

But, ongoing observations have a cost: communications, spacecraft operations and data analysis cost real money, and have a significant manpower demand, which adds up, so it is not obvious that it is cost-effective or worthwhile to run the secondary science, for the community overall - as opposed to the particular group wanting to use the particular capability.

So this requires some thought in practical implementation, in particular whether there is unique capability in instrumentation or observing parameters which ought to be made use of in spite of the cost and risk.

Talks will be online, as usual, video, audio podcasts and slides.
I'll add a link when the talks are ready.

If you ever wanted to know what the Earth's eigencolours are, this will be your chance.

Interesting talk on using EPOXI to monitor at a small set of known transiting exoplanets.
HAT-P-4, WASP-3, TrES-3, TsrES-2, HA-P-7, GJ436
cf Ballard et al in press arXiv0909.2875, Christiansen et al 2010 (arXiv0912.2132), Christiansen et al submtted

Interesting time coverage and decent photometry, caveat the CCD had degraded and was bootstrapped calibrated - could have introduced systematics.

Another interesting tidbit on EPOXI limited coverage of a μlensing event.

Discussion: a point that is bubbling is that basically the planetary/solar system people object to astrophysics "free--rides" on "their" missions - their division pays so no astrophysics should be done unless astrophysics pays.
But... many major astrophysics missions do planetary stuff, for "free" in many cases, or even send money to the planetary folks, notably Hubble.
So what's up with that, or do I misunderstand the arrangement.


More like this

Sometimes the next scheduled comet breaks up and disappears into the inky blackness so it's even nicer to get some not so prime results while men and mice move on to the next prime ...

The image of the Moon transiting the Earth confirms the very low lunar albedo. Since the night-time background contrast distorts the way we perceive the Moon (with scattered blue sunlight adding to the reflected lunar light during the day) most people are not aware what a dark lump the Moon is, compared to the Earth.

By Birger Johansson (not verified) on 19 May 2010 #permalink