{"id":12478,"date":"2020-05-12T17:08:12","date_gmt":"2020-05-12T09:08:12","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/dragon-solar-array-concerns-driving-duration-of-first-crewed-test-flight\/"},"modified":"2020-05-12T17:08:12","modified_gmt":"2020-05-12T09:08:12","slug":"dragon-solar-array-concerns-driving-duration-of-first-crewed-test-flight","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/dragon-solar-array-concerns-driving-duration-of-first-crewed-test-flight\/","title":{"rendered":"Dragon solar array concerns driving duration of first crewed test flight"},"content":{"rendered":"
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Artist\u2019s concept of a SpaceX Crew Dragon capsule docked at the International Space Station. Credit: SpaceX<\/figcaption><\/figure>\n

NASA astronauts Bob Behnken and Doug Hurley will be geared up for the long haul when they launch from the Kennedy Space Center on a SpaceX Crew Dragon spacecraft later this month, but they won\u2019t know exactly how long they will be in orbit until they are already aboard the International Space Station.<\/p>\n

The Dragon astronauts, both veterans of two space shuttle missions, could live and work on the space station for one to four months, according to NASA officials. The duration will primarily hinge on how well the Crew Dragon\u2019s solar panels hold up in the harsh environment of space.<\/p>\n

\u201cThe minimum mission duration is really about a month, and the maximum is 119 days,\u201d said Steve Stich, deputy manager of NASA\u2019s commercial crew program.<\/p>\n

The Crew Dragon test flight \u2014 set for liftoff at 4:33 p.m. EDT (2033 GMT) May 27 \u2014 will be the first launch of astronauts into orbit from the Kennedy Space Center since July 8, 2011, when the shuttle Atlantis rocketed into space on the final flight of the space shuttle program.<\/p>\n

If the mission launches May 27, the Crew Dragon is scheduled to autonomously dock with the International Space Station at 11:39 a.m. EDT (1539 GMT) May 28. Behnken and Hurley originally planned to fly to the space station for no more than a couple of weeks after launching on a SpaceX Falcon 9 rocket.<\/p>\n

The purpose of the Crew Dragon demonstration flight, named Demo-2 or DM-2, is primarily intended to test the commercial crew ship\u2019s performance with astronauts on-board. It follows a six-day unpiloted Crew Dragon test flight to the space station in March 2019.<\/p>\n

But NASA has approved an extension to the Demo-2 mission. Faced with the prospect of a period of months with just one U.S. astronaut aboard the space station \u2014 limiting opportunities for maintenance and repair spacewalks, and restricting the station\u2019s scientific output \u2014 NASA is planning to keep Behnken and Hurley at the $100 billion orbiting research outpost for up to four months.<\/p>\n

NASA astronaut Chris Cassidy launched from Kazakhstan on a Soyuz rocket April 9 with two Russian crewmates.<\/p>\n

\u201cThis launch will allow researchers around the globe to work with astronauts on-board the space station to undertake many different scientific investigations,\u201d said Kirk Shireman, NASA\u2019s space station program manager at the Johnson Space Center in Houston. \u201cThe SpaceX crew, with Chris Cassidy already on-board the International Space Station, will be doing experiments on physiology, cardiovascular experiments, physical and life sciences, testing out life support systems \u2026 and testing out habitation experiments for our future human space exploration.\u201d<\/p>\n

Behnken could also join Cassidy in a series of spacewalks to replace batteries on one of the space station\u2019s solar power trusses. The new lithium-ion batteries will be delivered to the space station later this month on an automated Japanese HTV supply ship.<\/p>\n

NASA originally intended to have SpaceX\u2019s Crew Dragon and Boeing\u2019s Starliner crew capsules certified by now for operational crew rotation flights to and from the space station. But development delays in both programs \u2014 originally due to NASA funding shortfalls, then caused by a series of technical problems \u2014 have pushed back the start of regular commercial taxi service to the space station by years.<\/p>\n

NASA has signed agreements with SpaceX worth more than $3.1 billion since 2011 to pay for development of the Crew Dragon spacecraft. SpaceX has also pitched in an undisclosed sum of its own money to help fund the program.<\/p>\n

Boeing and NASA have a similar series of contracts valued at nearly $5 billion in a public-private partnership to develop the Starliner spacecraft. The Starliner failed to dock with the space station on an automated test flight in December, and Boeing plans to repeat the orbital demonstration mission later this year before NASA clears the Starliner to fly astronauts.<\/p>\n

The Russian Soyuz capsule has been the only spacecraft capable of carrying crews to the space station since the space shuttle program ended. NASA has paid the Russian government approximately $3.9 billion since 2006 to purchase Soyuz seats for astronauts from the United States and the station\u2019s other international partners, according to a report last year by NASA\u2019s inspector general.<\/p>\n

NASA expects to end payments to Russia once the new U.S. crew ships are operational. Under the space agencies\u2019 current plans, U.S. astronauts will continue flying on Soyuz spacecraft and Russian cosmonauts will launch and land on the new U.S. vehicles under a barter arrangement, with no funds exchanged.<\/p>\n

But Russian officials say they are not assigning cosmonauts to missions on U.S. vehicles until they are flight-proven.<\/p>\n

Flush with NASA money, Russian space contractors doubled the production of Soyuz crew capsules for launches beginning in 2009 to meet the demand for astronaut transportation to the space station. After NASA\u2019s last Soyuz seat purchase in 2017, the schedule for Soyuz crew missions has been cut back to two flights this year.<\/p>\n

Cassidy took the last Soyuz seat under NASA\u2019s control, but the agency is negotiating to purchase one more round-trip Soyuz ticket  for a launch in October.<\/p>\n

NASA and SpaceX hope the first operational Crew Dragon mission, designated Crew-1, could be ready to launch some time this fall. But NASA wants a backup plan to ensure a U.S. astronaut can get to the space station in case of additional delays.<\/p>\n

Regular crew rotation flights using the Crew Dragon capsule could last up to 210 days, but NASA and SpaceX are setting tighter limits for Behnken and Hurley\u2019s mission due to the experimental nature of the Demo-2 test flight.<\/p>\n

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NASA astronauts Doug Hurley and Bob Behnken address the media in October 2019 at SpaceX headquarters in Hawthorne, California. Credit: NASA\/Aubrey Gemignani<\/figcaption><\/figure>\n

Stich said preflight analyses show the Crew Dragon spacecraft set to fly the Demo-2 mission can safely remain in orbit for up to 119 days, or about four months, based on a \u201cworst-case\u201d prediction for how the ship\u2019s solar arrays will perform in orbit.<\/p>\n

\u201cAny solar array in low Earth orbit tends to degrade a little bit over time,\u201d said Stich, a former space shuttle flight director. \u201cIt turns out the atmosphere has a little bit of oxygen in it \u2014 it\u2019s called atomic oxygen \u2014 so there\u2019s a little bit of degradation in the ability of that solar array, the cell itself, to generate power.\u201d<\/p>\n

Once the Crew Dragon is docked to the space station, SpaceX and NASA engineers will assess data the solar arrays\u2019 performance and efficiency to determine when to bring the crew back to Earth.<\/p>\n

\u201cWhat we\u2019ll do is we have this curve of what we expect that degradation to be over time,\u201d Stich said. \u201cWe can kind of look at the power the arrays generate each day, and kind of plot that against this prediction, and that can give us the overall total capability.\u201d<\/p>\n

The solar arrays on SpaceX\u2019s new-generation Dragon spacecraft, called Dragon 2 or Crew Dragon, are mounted on the body of the spaceship\u2019s unpressurized trunk. The trunk is attached to the aft end of the Dragon\u2019s pressurized crew cabin, and a thermal radiator sits on the opposite side of the cylindrical trunk from the solar arrays.<\/p>\n

SpaceX\u2019s previous Dragon design, which retired earlier this year after 20 unpiloted cargo delivery flights to the space station, used unfolding solar panels to generate electricity.<\/p>\n

\u201cWe looked at the rest of the vehicle, (and) we don\u2019t see any other life limiters,\u201d Stich said in a May 1 press conference. \u201cWe looked at the pumps on the thermal system, we looked at the propulsion system, all the other components, when we talked about extending the mission, and the solar arrays are the only one really that have a little bit of a poke-out.<\/p>\n

\u201cSo we\u2019ll just kind of watch their performance in flight and be able to make a good decision about how long to stay docked,\u201d he said.<\/p>\n

NASA is balancing the objectives of the Demo-2 test flight with satisfying the agency\u2019s desire for extra manpower on the space station.<\/p>\n

\u201cWe\u2019re really trying to do both a test flight with this vehicle, and also have the vehicle docked to station to allow Bob and Doug to augment the station crew,\u201d Stich said.<\/p>\n