Discovery AO Details Emerge

Details of the next NASA Discovery Program Mission Announcement of Opportunity have been released by NASA. The draft of the AO will be released next month, but a few of the key elements of the document are now available. Discovery missions are low-cost, Principal Investigator-led projects. For this AO, any solar system target is acceptable, excluding the Earth and the Sun. So Mars missions would be acceptable.

For an Io mission like IVO, there are a few key details to consider. First, Advanced Stirling Radioisotope Generators (ASRGs) can be used as power sources for a proposed mission. If a proposer wishes to use them, NASA will provide two of them at no cost to the project's cost cap. This decision will allow the missions developed under the DSMCE concept study program to be proposed for this AO. However, there is one problem for the Io Volcano Observer. The cost cap for the next Discovery mission is currently set at $425 million (FY10). This is $25 million less than planned for in the DSMCE program, and the IVO team already needed to find a way to cut $21 million from the cost estimate provided by JPL's Team X. So the current cost cap would make it difficult to do a mission like IVO even with the power sources provided by NASA. One point I should make though is that I am not sure if the $471 million cost estimate for IVO by Team X included the launch vehicle as that will be provided by NASA at no cost to the mission's cost cap.

According the announcement by NASA, 2-3 missions will be approved to continue to Phase A, allowing for a refinement of the mission concepts. After the completion of Phase A, one mission will be selected to go to Phase B and then on to mission completion. This setup is probably intended to prevent some of the cost overruns that have plagued many of the recent Discovery program missions like MESSENGER and Dawn. Downselection to Phase A should occur in July 2010 and then to the single mission in November 2011.

Tip of the plutonium to Van Kane.

EDIT 07/14/2009: Since this post seems to be pretty popular for people looking for info on the Discovery AO, I should point out that launch vehicle costs (along with ASRGs) are excluded from the cost cap, which should make it was easier for proposals like IVO to meet the $425 million (FY10) limit.

Link: NASA intends to release a Discovery Program Draft AO [nspires.nasaprs.com]

Hubble Servicing Mission Launches

The Space Shuttle Atlantis launched earlier today to perform the fourth and last servicing mission of the Hubble Space Telescope. This Shuttle mission should restore the functionality of the Advanced Camera for Surveys (ACS) and the Space Telescope Imaging Spectrograph (STIS). The shuttle astronauts should also install two additional instruments: the Cosmic Origins Spectrograph (COS) - a high-spectral resolution ultraviolet spectrometer - and the Wide Field Camera 3, an upgrade from WFPC2.

Hubble over the years has made a number of discoveries at Io including observing surface changes between Voyager and Galileo (such as a major eruption at Ra between 1994 and 1995) and sulfur gas in Pele's plume. These discoveries were made using the full-set of instruments onboard the space telescope, and no doubt these new instruments would certainly be useful for the study of Io, particularly studying the gases in Io's atmosphere using the COS spectrometer. Because of the high demand on telescope time, Hubble is not well suited for change detection, but certainly comparisons between any chance images of Io could be used for this purpose, but they would need to be large changes like the one at the Ra Patera eruption.

Link: Hubble Servicing Mission 4 [sm4.gsfc.nasa.gov]

My 365 Days of Astronomy Podcast

My podcast for the 365 Days of Astronomy should be online later today, if it isn't already. The topic of my podcast is "It's the Season for Eclipses in the Jupiter System." Here is the summary I submitted for this edition:

In 2009, as it does every six years, the Jupiter system experiences equinox. While Jupiter's low axial tilt makes the passing of season much less noticeable than on Earth, Mars, or Saturn, equinox does bring a season of eclipses for Jupiter's moons. From Earth, astronomers can observe these eclipses as well as occultations, when one moon passes in front of another. Today, we will discuss the useful science gained from eclipses and occultations as well as a few of the eclipses coming up in the Jupiter system, focusing primarily on Jupiter's innermost large moon, Io.

I cover both the equinoxes to be experienced by Jupiter and Saturn in the podcast, looking at the unique events that can be observed during the months surrounding equinox as well as look at the types of changes that occur in these two systems as the seasons change.

I hope you all have a chance to check it out! You can also read the blog post that was the genesis for this podcast.

Link: 365 Days of Astronomy - It's the Season for Eclipses in the Jupiter System [365daysofastronomy.org]