Ice, Cloud,and land Elevation Satellite-2. Credit: Orbital Sciences

WASHINGTON — NASA is proposing to pull the plug on the 10-year-old Mars Opportunity rover, scale back several space technology projects and likely delay the overbudget ICESat-2 mission as it seeks to make ends meet within the confines of the $17.5 billion budget the agency is seeking for 2015.

The agency also had to abort plans to order an extra commercial cargo flight to the international space station, according to a 700-page budget justification document released March 11.

Citing a shortage of funds within the international space station program, NASA has now scrubbed plans to add another commercial cargo flight to its 2015 manifest, which covers missions scheduled between Oct. 1, 2014, and Sept. 30, 2015.

“NASA has eliminated one previously planned [fiscal year] 2015 cargo flight from the manifest as the agency balances ISS requirements with appropriated funding,” the agency wrote in the budget justification document. 

NASA spokesman Trent Perrotto said this flight would have been in addition to the 20 ISS cargo resupply missions Orbital Sciences Corp. and Space Exploration Technologies Corp. are scheduled to complete by 2016 under Commercial Resupply Services contracts signed in 2008 and worth a combined $3.5 billion. SpaceX has flown two of its 12 contracted supply runs; Orbital has flown one of its eight.

The Space Operations Mission Directorate, which manages the international space station, got roughly $3.7 billion from Congress for 2014, about $100 million less than NASA asked for that year, and some $200 million less than what the agency seeks for 2015.

Within its Earth Science Division, NASA is overhauling its cost and schedule estimates for the Ice, Cloud, and land Elevation Satellite (ICESat)-2. NASA said in December that ICESat-2 was likely to exceed its estimated $559 million development budget by at least 15 percent because of technical difficulties with its only instrument, the Advanced Topographic Laser Altimeter System.

The expected breach triggered a mandatory report to Congress, which was delivered Jan. 29 but not publicly released.

As recently as October, ICESat-2 was slated to launch by mid-2017 aboard a Delta 2 rocket. That date is expected to slip as NASA establishes a new baseline for the mission — a replanning effort the NASA’s budget justification says will be completed by Sept. 30. 

NASA is also halting development of the Orbiting Carbon Observatory-3 instrument that was to launch to the international space station in 2016. The agency “expects other missions to provide sufficient data on atmospheric carbon levels,” according to the budget document.

Elsewhere in Earth Science, delivery of the Stratospheric Aerosol and Gas Experiment-3 to the ISS will be delayed from August to March 2016 because of a holdup with the payload’s European Space Agency-provided pointing system.

NASA’s budget justification expands on the reasons it gave the week of March 4 for canceling the Astrophysics Division’s $1.1 billion Stratospheric Observatory for Infrared Astronomy, saying the telescope-equipped jetliner’s “contributions to astronomical science will be significantly less than originally envisioned.” Grounding the observatory — which was due to begin making regular science flights this year — would save the agency about $85 million a year, NASA said.

NASA’s Planetary Science Division also is being asked to make a tough trade-off in order to free up funds for continued operation of the nearly 17-year-old Cassini Saturn probe. Come 2015, NASA’s Opportunity Mars rover, the longest-lasting of two identical rovers that landed on the red planet in 2004, will be shut down, NASA’s budget justification says.

NASA’s budget justification also outline some significant changes within the Space Technology Mission Directorate. For starters, NASA has delayed launch of its Sunjammer solar sail demonstration mission indefinitely, pending a review. The mission was supposed to fly as a secondary payload on a SpaceX Falcon 9 rocket provided by the Air Force to launch the National Oceanic and Atmospheric Administration’s Deep Space Climate Observatory satellite in 2015.

“As Sunjammer approached the Technology Demonstration Program’s annual review in October, several key integration issues were identified that increased the schedule risk,” NASA spokesman David Steitz wrote in a March 13 email. “The project is now developing a new schedule and is assessing available rideshare options.” 

The Deep Space Climate Observatory, meanwhile, is still set to launch on a Falcon 9 in 2015, John Leslie, a spokesman for the National Oceanic and Atmospheric Administration, wrote in a March 12 email.

NASA is also canceling a planned spaceflight demonstration of cryogenic propellant storaged, but ground-based demonstrations will continue, the budget justification says. Orbiting propellant depots have been cited by NASA as an enabling technology for deep-space missions.

Finally, a laser communications relay demonstration NASA hopes to fly as soon as 2017 a hosted payload on an unspecified commercial communications satellite built by Space Systems/Loral is hurting for funds and NASA will be looking to industry to help defray cost.   

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Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...