SpaceX: From Bothering Bovines to Revolutionizing Rockets
SpaceX are continuing to make progress on several key projects as they head into a busy period of launches. With the debut launch of their Falcon 9 v1.1 rocket still on for September, an eye to the future for both their launch vehicles and spacecraft was highlighted over recent days, with the most spectacular event conducted by the Grasshopper test vehicle – as much as it was less-appreciated by some of the locals.
Preparations for an upcoming launch are continuing at SpaceX’s SLC-4E pad at Vandenberg Air Force Base (VAFB) in California.
The launch will debut the upgraded Falcon 9 rocket, known as the v1.1, which was the subject of extensive testing at the company’s Rocket Development and Test Facility in McGregor, Texas.
With the successful conclusion to development and acceptance testing on the core’s nine Merlin 1D engines, the vehicle is currently being prepared at Vandenberg for its Wet Dress Rehearsal (WDR) – scheduled for the last week in August (L2) – and Hot Fire test.
The mission is tasked with launching the CAScade, Smallsat and IOnospheric Polar Explorer (CASSIOPE) – a made-in-Canada small satellite from the Canadian Space Agency – into orbit, early in September. The launch date will be firmed up once the on-pad testing and vehicle integration tasks have been completed.
A successful mission for the upgraded launch vehicle will allow SpaceX to proceed toward the launch of what will be the debut launch of a geostationary satellite, with the lofting of the SES-8 spacecraft from Cape Canaveral Air Force Station in Florida.
In a sign of SpaceX’s ability to hit the ground running with a busy launch schedule, an image was recently published showing several stages lined up on the factory floor at the company’s facility in Hawthorne, California.
The photo shows the first stages for flights 7, 8, 9 – along with second stages for flights 8 and 9 – on the factory floor, with one unidentified stage and octoweb inside “SpaceX Falcon 9 spray booth”.
Since the photo was taken, the core for Flight 7 (F9 S1-007) was shipped to the McGregor Test Facility for its acceptance test firing, as was the second stage (F9S2-007).
Following the development test firings on the F9 S1-006 core that will launch with CASSIOPE, stages are now expected to head in and out of Texas at a more rapid pace, with the objective of “simply” completing acceptance testing.
SpaceX officials usually inform the local media of firings, to provide nearby residents with a heads up of the loud noise and localized shaking that accompanies the ignition of their stages.
One of the reasons SpaceX upgraded their Falcon 9 rocket relates to its future as the F9-R (Reusable). Essentially the v.1.1 and F9-R are the same vehicle, although the upgraded F9 will not fly with the key reusable hardware – such as landing legs – until a later date.
However, that technology is already being tested at McGregor, with a number of stunning successes.
The test system is called the Grasshopper, which is tasked with testing hardware elements such as propulsive targeted landing and its own landing legs structure.
Seven tests have been conducted, with Grasshopper showing its ability to carry out incremental objectives, opening with a short hop of just six feet during Test 1, through to a massive 1,066 foot leap during Test 6.
The seventh test, carried out last week, proved to be the most stunning, as the Grasshopper did much more than rise upwards before returning to its concrete pad.
For this test, conducted on August 13, the test vehicle completed a divert test, flying to a 250m altitude with a 100m lateral maneuver before returning to the center of the pad.
While the video of the test was greeted with a huge outpouring of positive reaction from the space flight community, a herd of local cows were less enthusiastic, showing their disdain for the noise by rampaging away from the scene in front of one of the cameras filming the event.
Ultimately, the test demonstrated the vehicle’s ability to perform more aggressive steering maneuvers than have been attempted in previous flights.
It is also understood that this may have been the final test for this Grasshopper in Texas, although that is yet to be confirmed.
Although SpaceX have a salvo of commercial satellite launches to complete through the remainder of the year, the opening launch of 2014 will see the return of the Dragon spacecraft, as it continues preparations for its fourth mission to the International Space Station (ISS).
Known as CRS-3 (SpX-3), Dragon will be tasked with lofting full launch and return complement of 1,580kg/3,476lb of payload. It is also likely to contain a rack, for the use of transporting – and returning – EMU hardware relating to the leaky spacesuit that prematurely ended the recent EVA-23.
Should Luca Parmitano’s faulty suit hardware return to Earth onboard the Dragon, it will once again show the vital role the SpaceX spacecraft can provide NASA, given no other ISS-visiting vehicle can provide such a large downmass capability.
The CRS-3 Dragon will also sport new check valves on its thruster system, following the incident that occurred just after the CRS-2 Dragon separated from the Falcon 9’s Second Stage earlier this year.
The problem was seen in the propulsion system – a set of four “quads” of thrusters on the Dragon, vital for attitude control and required burns en route to its destination. The issue was seen during priming phase, as Dragon prepared to fire up its thruster systems by pressurizing the fuel tanks via the injection of gaseous helium.
With three of the four quads at a lower than required pressure, only “Quad 1” remained online, which was not enough to ensure Dragon could maintain attitude control.
The drama was played out in an unusual fashion, with SpaceX CEO and Chief Designer Elon Musk seeing his short tweets relayed as part of NASA TV’s live coverage, while thousands of space flight fans crashed websites – including NASASpaceFlight.com for 20 minutes as many hundreds of people hit refresh every second on the live coverage section – as they desperately tried to gain information on the spacecraft’s status.
Although the initial plan was to deploy Dragon’s solar arrays once two Quads were available, SpaceX controllers decided to unfurl the arrays with only one Quad working. This proved to be helpful for the unstable Dragon, with Mr. Musk describing it as not unlike an ice skater stretching out her arms during a spin maneuver to slow the rotation.
Evaluations of the propulsion system concluded it was was being caused by either a blockage in the helium line, or – as it later turned out to be – a sticky check valve. The solution was to “jack-hammer” the valves in the system by commanding them to cycle on and off several times in succession. This proved to be successful as all the Quads began to return to life.
In mitigation of a repeat problem with the CRS-3 Dragon, SpaceX have installed new check valves and refined their operational plan.
“The Dragon check valve failure was handled very well in real-time,” noted ISS manager Mike Suffredini to the latest meeting of the Aerospace Safety Advisory Panel. “Dragon did not violate the criteria for continuing proximity operations and met all of the failure tolerance requirements, but the team was puzzled on how it failed.”
The ASAP heard about the discussion on root cause at its fact-finding meeting, where it was noted SpaceX and its vendor found some faults with the quality test procedure that was done at the factory, as well as with the prime contractor’s acceptance test procedure.
“It was not a ‘test as you fly’ case,” the meeting was told. “They fixed the process failures and learned from that. NASA was pleased with the lessons-learned from this incident, and SpaceX now has a better approach with the vendor. New valves with the new procedures have been installed for the next Dragon flight.”
The CRS-3 Dragon is set for its first ride on the upgraded Falcon 9 v1.1 next year, after receiving an updated berthing window that opens on January 17, 2014.
While SpaceX’s Commercial Resupply Services (CRS) contract will see a series of Dragons visiting the orbital outpost, the spacecraft is one of three major competitors for NASA’s Commercial Crew Program contract.
Should SpaceX win through the down-select process, Dragon will move to transporting NASA astronauts to the Station in the second half of this decade.
Currently in the Commercial Crew Integrated Capability (CCiCap) initiative phase of development, SpaceX recently reviewed the systems critical to sustaining crews in orbit and returning them safely to Earth, ranging from basic life support functions – including pressurizing Dragon with breathable air, to stocking the capsule with enough food and water – for as many as seven crew members.
“NASA has learned a lot about keeping our astronaut crews safe throughout a mission, and we don’t want those lessons to be forgotten,” noted Ed Mango, NASA’s CCP manager. “So, we’re sharing a lot of what we already know, and the company is adding its own innovations to suit its needs and meet its challenges.”
In what was a Preliminary Design Review (PDR)-level meeting, SpaceX engineers presented NASA representatives with detailed analyses of Dragon systems, including hardware and software aboard Dragon that would be used to aid the spacecraft’s rendezvous and docking operations.
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SpaceX also overviewed the spacecraft’s software design, along with its relation to crew and ground control operation on orbit.
The review was the seventh milestone for SpaceX under CCiCap. The company continues to be on track to complete all 15 of its CCiCap milestones by the summer of 2014.
Following this review of the orbit and entry systems – along with the previous completion of the ground systems and ascent reviews – SpaceX will now proceed towards finalizing detailed designs for its integrated space transportation system.
“SpaceX’s Dragon spacecraft was designed from the outset to accommodate the upgrades necessary to safely carry people, so we’re excited to have reached the halfway point in our agreement with NASA to design those features,” added Gwynne Shotwell, SpaceX president and chief operating officer.
“As we leverage our experience successfully delivering cargo both to the International Space Station and back to Earth, SpaceX remains committed to providing the safest manned flights ever conducted.”
(Images: L2 Content, NASA, SpaceX.)
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