Detecting Extra-Solar Planets With Suborbital Flight

Brad Cheetham of U of CO is giving a talk on seeing extra-solar planets using suborbital vehicles and star shades. Kepler and Hubble find planets by inference from star wobbles, but they’re proposing to actually shield the star with a shade to allow planets to be actually be seen. Showing a simulation of what earth would look like from deep space with the sun shielded. Allows planets to be viewed even if we’re not in their orbital plane. Also allow spectroscopy to detect habitability (carbon, hydrogen, oxygen in the atmosphere). Flagship mission would use a telescope with a star shade at ES-L2. Critical technologies — precise orbit/attitude control, precision edges/deployment, opaque membranes, etc. Need preliminary observations prior to selection of flagship mission targets. Need to work with them suborbitally over next three years, including some astronomy good enough to publish. Suborbital can prove out technology very cost effectively, allowing design iteration and refinement. Need a couple hundred million for the ultimate mission but this can provide an affordable way of technology advancement until funding is found. Have a proposal in using Masten Xaero with a starshade that flies over a ground-based telescope. Trajectory has to be accurate to ten centimeters. Can start as low as one kilometer and go higher as techniques improve. Ultimately hope to image an earth-sized planet in the habitable zone at Alpha Centauri (binary system) using suborbital. Holding alignment major technical challenge, using GBORN receiver (cigarette-sized, one or two watts) for augmented GPS solution using cell towers, etc. for high precision. Think it has potential to map Alpha Centauri and Tau Ceti systems within three years, with ability to map more distant stars in next decade as technology goes into orbit.

10 thoughts on “Detecting Extra-Solar Planets With Suborbital Flight”

  1. Has anyone talked about the proposal to use telescopes on suborbital flights to detect vulcanoids (asteroids in a certain orbital zone within the orbit of Mercury)?

  2. No, though I haven’t looked through the program in detail, and haven’t really been sitting in on the sessions where they would. This was actually a walk-on talk that Alan heard about on Sunday night, presented in a session on the use of suborbital for technology maturation — it’s not in the program. But I blogged it because I thought it was interesting.

  3. My understanding is that extrasolar planet observations would have to be ridiculously delicate operations with hours of integration time. Do they have a method which they can use in the minutes out of atmosphere that a suborbital flight affords?

    Cool idea though. I’m all for trying it.

  4. Yeah, when Brad and Dr Cash told me about this idea, I thought it was really cool as well. Wanted to blog about it, but decided to let them pick the timing of when to let the info out. Glad they’re out in the open with the idea though. I’ll be a lot of fun (and a crazy amount of hard work) if they can get money for this.


  5. They’re going to want multiple starshades if the first one proves practical. It’s hard to see how a suborbital would have any time in the right position to work?

  6. How about we levitate a very low mass starshade using light pressure, say with a microwave beam? It could be suspended in place above the atmosphere. This might be best for near UV observation, where the thermal glow from the shade would be lowest.

  7. “Kepler and Hubble find planets by inference from star wobbles”

    Sort of, but not really. That can be done relatively easily with ground-based telescopes — Earth’s atmosphere does not interfere with measuring radial velocity variations down to meters per second. Space telescopes hve been used in a few cases to detect angular displacements caused by orbiting planets, but these measurements are at the limits of resolution.

    Space-based telescopes have detected so many extrasolar planetary systems because they can measure the minuscule dimming of starlight when a planet passes in front of its star during a transit (that is, an annular eclipse of the star by the planet). For that you need a precision of about 0.001 magnitude, and you just can’t get that with ground-based telescopes because of scintillation and variable atmospheric extinction.

    I think it makes WAAAAY more sense to use the starshade method of direct observation with a space telescope instead of with a ground-based observatory. Sure, you could use one of the BIG telescopes here on Earth as your light bucket with a suborbital starshade, but the difficulty of accurately positioning the starshade within the short time window would be outweighed by the essentially unlimited window for positioning and observing if both the shade and the telescope were in space.

    In other words, the New Worlds Mission for the James Webb Space Telescope, or some other space telescope.

    For that matter, I suspect it would make sense to use the dark limb of the Moon as a starshade, if you could move a space telescope into the right position. Lunar occultations have been used for decades to resolve very close binaries. Alas, the problems with trying to use lunar occultations to detect planets with ground based telescopes include: (1) as seen from the Earth, the Moon doesn’t pass in front of very many “interesting” stars, and (2) the Moon moves too fast and doesn’t allow extended observation.

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