Priorities list issued to direct heliophysics research
BY STEPHEN CLARK
Posted: August 18, 2012
NASA should shift its heliophysics research strategy to include more nimble, less expensive satellite missions in light of a tight budget already devoted to several costly projects this decade, top scientists reported this week.
The National Research Council report, which covers programs between 2013 and 2022, recommends an addition of $70 million per year to NASA's Explorer program, portfolio of small and medium-class missions with limited costs and focused science objectives.
The extra funding for Explorer missions would be offset by reductions elsewhere in NASA's heliophysics program, according to Daniel Baker, chair of the decadal survey team and an astrophysicist at the University of Colorado at Boulder.
"We're not asking for new funds," Baker said. "We're living within the envelope that's been established for NASA."
The budget change would allow for the selection of medium-class Explorer missions, which were discontinued due to lack of funding, according to the report. Only small Explorer projects are currently in the pipeline.
Thomas Zurbuchen, vice chair of the decadal survey committee and a professor at the University of Michigan, said the Aerospace Corp. provided independent cost estimates for all of the report's proposed missions, giving scientists confidence the recommended projects will meet NASA's tight budget.
But NASA's No. 1 priority in heliophysics should be continuing ongoing missions and developing programs already in development. Those projects include the Radiation Belt Storm Probes due for liftoff Aug. 23 and the Interface Region Imaging Spectrograph - a small Explorer mission - scheduled to launch in January.
The $686 million RBSP mission will make the most detailed measurements of Earth's donut-shaped radiation belts, and a solar telescope on the $180 million IRIS mission will observe the flow of energy emanating from the sun and powering the solar wind.
The Magnetospheric Multiscale mission, or MMS, will launch as soon as late 2014. A fleet of four satellites will study the processes of plasma physics and magnetic reconnection from Earth orbit. NASA projects the MMS mission will cost $857 million.
NASA's partnership on the European Space Agency's Solar Orbiter mission, which includes instrument contributions and a United Launch Alliance Atlas 5 launch vehicle, is valued at approximately $400 million.
After launching in January 2017, Solar Orbiter will fly as close as 26 million miles from the sun, less than one-third the average distance of Earth. The spacecraft will sample the solar wind shortly after it is ejected and conduct remote sensing imaging to observe the sun's corona and the solar atmosphere.
The hardened probe will orbit inside the sun's corona - as close as 3.7 million miles from the surface - during its science mission. Solar Probe Plus is expected to launch in 2018.
Many of the objectives of NASA's ongoing heliophysics projects were cited in the solar science community's last decadal survey in 2003.
NASA's projected budget through the end of the decade will not allow for a launch of another large mission after Solar Probe Plus until the early 2020s.
Scientists ranked three mission concepts as the top priorities for NASA's Solar-Terrestrial Probes program, which the decadal survey panel recommended to be cost-capped at $520 million to ensure a new mission launches every four years.
The next new mission, tentatively called the Interstellar Mapping and Acceleration Probe, would follow up on discoveries on the boundary between the solar system and interstellar space made by NASA's IBEX satellite. IMAP could lift off in the early 2020s, in time to conduct tandem observations with NASA's Voyager deep space probes now on the verge of entering interstellar space.
Follow-on probes in the 2020s and 2030s should include a project to investigate the link between space weather and atmospheric weather on Earth and a mission to study how the magnetosphere and ionosphere respond to solar and magnetospheric forcing, according to researchers.
NASA's largest class of heliophysics missions - the Living With a Star program - should begin development later this decade of the Geospace Dynamics Constellation for launch around 2024. A fleet of six satellites would look into how Earth's atmosphere absorbs energy from the solar wind.
Another decadal survey recommendation was a suggested rechartering of the U.S. government's space weather program, including separating funding lines for research and observations.
In the report, scientists pressed the need for continuous solar wind observations from the L1 libration point, a gravity-stable point a million miles from Earth. The Advanced Composition Explorer, which currently returns solar wind data for space weather forecasters, has surpassed its design life and has been in space for nearly 15 years.
NASA, NOAA and the U.S. Air Force plan to launch the Deep Space Climate Observatory, or DSCOVR, as soon as 2014 to pick up solar wind measurements at the L1 point.