Effective September 1, 1999, before being posted to this site, the information contained in this time line is reviewed by the NASA X-33 Program.

Many thanks to Dill Hunley, Historian, NASA Dryden Research Center; and Jim Cast, NASA Headquarters, for supplying the news releases and photographs found here.

1999 July 6

The roll-out of the first of four X-33 (XRS-2200) aerospike engines took place today. This was a major event for Rocketdyne, and the X-33 Program. Speakers at the even included Rocketdyne Vice President and General Manager Byron Wood, Rocketdyne Advanced Propulsion chief Steve Bouley, X-33 Aerospike Program Manager Rick Hilscher, and Lockheed Martin X-33 Program Manager Cleon Lacefield. The following day, the engine will be trucked to NASA's John C. Stennis Space Center in Mississippi for testing. Of the four X-33 aerospike engines that Rocketdyne is building, the first two will serve as test engines, while the second set of four engines will be fitted to the X-33 vehicle. Delivery of the vehicle engines likely will not occur until November or December. The first X-33 flight then will not take place until July 2000, as currently planned.

1999 July 7

The first X-33 aerospike engine left Rocketdyne this day for NASA's Stennis Space Center in Mississippi. Testing of the engine is scheduled to begin in mid-August. Also scheduled for mid-August is testing of the liquid hydrogen tank.

1999 July 13

NASA's John C. Stennis Space Center in Mississippi announced that the first XRS-2200 linear aerospike engine had arrived there over the preceding weekend.

1999 July 26

Testing of the first XRS-2200 linear aerospike engine at NASA's John C. Stennis Space Center in Mississippi has been delayed until September.

1999 July 30

The first engine has been installed in the test stand fixture at NASA's Stennis Research Center. Some facility work is still in process for making the test stand ready. Foam machining work has slowed the completion of modifications to liquid hydrogen tank #2 until the first week of August. Liquid hydrogen tank #1 is still on track for a completion date of August 15th at Sunnyvale, California. The right body flap has been shipped to begin its tile installation. The left body flap should be complete and ready for shipping in the first part of August.

1999 August 8

Delays continue. NASA's Stennis Research Center reports that they are 50 engine parts short of having a complete engine for the upcoming aerospike engine hot fire tests. NASA's Marshall Space Flight Center still hasn't established a Test Readiness Review date for the upcoming liquid hydrogen tank tests.

1999 August 24

Gene Austin, NASA X-33 Program Manager, and Cleon Lacefield, Skunk Works, represented the X-33 program during a NASA X-vehicle press conference held today 1 - 3 PM EDT at NASA Headquarters broadcast over NASA television. They joined NASA and industry program personnel, including Gary Payton, from the X-34 and X-37 programs. View "slide show" of X-33 presentation vugraphs.

1999 August 30

In a draft General Accounting Office (GAO) report, according to Aerospace Daily, delays in the X-33 Program may have an impact on NASA's decisions regarding upgrades to the Shuttle. It also noted that the Skunk Works could charge X-33 cost overruns to other federal programs as independent research and development (IRAD) overhead. As a result, an estimated $286.6 million industry contribution to the X-33 program may amount to only $125.4 million. The GAO report also stated that, according to Aerospace Daily, NASA has lowered its performance objectives. Industry will receive a $60 million payment after five flights, instead of $75 million for 15 flights. NASA responded that they altered the performance requirements after Lockheed Martin agreed to increase its contribution by $75 million. As for the IR&D deductions, the actual amount, NASA stated, may turn out to be lower after an audit.

1999 August 30

NASA announced that testing will begin on the XRS-2200 (X-33) linear aerospike engine "in September." The engine arrived July 10 at NASA's John C. Stennis Space Center in southern Mississippi. Stennis personnel will conduct a total of 41 test firings on four engines (two test engines and two flight engines). The first 25 firings will involve two flight engines and one test engine, each tested individually. The first six engine tests (lasting five seconds or less) will address engine ignition and start sequence development. Upon successful completion of those tests, eight more tests will take place lasting a maximum of 250 seconds to verify engine performance at various mixture ratios and power levels, as well as to demonstrate thrust vector control. Planned total test duration on the first test engine is 1,142 seconds.

1999 August 31

Aerospace Daily reported that Rocketdyne's XRS-2200 linear aerospike engine is scheduled for its first full-up hot-fire test on September 11. This will mark the beginning of engine tests for the X-33 that will last into next summer, when the X-33 is scheduled to being test flights. Chilldown tests on the first of the four XRS-2200 engines that Rocketdyne is building for the X-33 program are to begin this week at NASA's Stennis Research Center in preparation for the first hot-fire test. This first engine is only intended for testing, not flight. It will be subjected to 14 tests this fall. The combined duration of all 14 tests will be 1,142 seconds (about 19 minutes). These will be tests of the ignition system, the engine start sequence, and engine performance at various fuel mixture ratios. In November, the first flight engine is scheduled to begin a six-test series, lasting a total of 572 seconds (about 9.5 minutes). A series of five tests of the second flight engine is scheduled to begin in December. These engine tests also will look out engine performance with one of its power packs out, because the pair of XRS-2200 engines powering the X-33 are designed to keep running despite a power pack failure. The power packs already have undergone testing at Stennis for more than 1,500 seconds (25 minutes) without a problem.

1999 September 7

NASA announced that one of the X-33 composite liquid hydrogen fuel tanks would soon undergo a series of pressure and stress tests at NASA's Marshall Space Flight Center in Huntsville, Ala.

1999 September 10

Major progress was achieved with the Extended Range checkout. All technical issues having been resolved, a Combined Systems Test was completed on this date.

1999 September 11

The hot-fire of the X-33 aerospike engine is scheduled for this date, 11 September, at NASA's Stennis Space Center. (The scheduled test firing did not take place. A hydrogen leak and subsequent fire occurred on the engine stand facility. Damage was minimal.) In addition, the test readiness review for X-33 liquid hydrogen tank no. 2 was completed at Marshall Space Flight Center on 30 August, with an approval to continue with the tank tests. A partial liquid nitrogen fill of the tank was completed on 7 September. Meanwhile, liquid hydrogen tank no. 1 has been completed, and is awaiting transport aboard the Super Guppy.

A local ER-2 (Extended Range) flight was performed on this date. This flight provided data necessary for validating the X-33 Extended Range.

1999 September 15

The final ER-2 flight was completed on this date between Dugway and Dryden. This and the previous September 11 flight provided data necessary for validating the X-33 Extended Range.

1999 September 22

The X-33 Quarterly Review was held at Marshall Space Flight Center. No new issues arose. Meanwhile, construction of the vehicle continued. The port and starboard flex lines have been mated to the liquid oxygen tank. Bracket connection and leak checks are in progress. Connection of the flex lines to the downcomer was scheduled for this week. The GPS antennas passed qualification. Installation on the thrust structure continued. Plumbing on the forward ballast bulkhead is complete, though without insulation. The remaining two elevons were received from B.F. Goodrich, and they will be shipped to Oceaneering. This will constitute the full set of flight controls workable for tile and blanket installation. The liquid hydrogen tanks continue to be troublesome. Tank no. 2 is undergoing repairs for leakage. The sealant liner on the outside longerons is delaminating. A borescope will be used next week to inspect the inside liners.

1999 September 25

Hot fire testing of aerospike engine no. 1 did not occur today, because an EMA controller unit failed. Moreover, a replacement unit has a noise problem.

1999 September 28

NASA issued a press release updating progress on the X-33 vehicle. Items covered included preparations for testing the aerospike engines and the liquid hydrogen tanks, testing of the launch umbilicals (which connect the X-33 to the cryogenic gas, power, and computer lines while it sits on the launch pad) at NASA Kennedy Space Center, installation of the vehicle's two 3-foot by 4-foot aluminum interface panels on the aft section (accomplished in August) and two 15-foot-tall carbon steel tunnels that will house the interface panels, completion of about 90 percent of the X-33's software, installation of the avionics bay, and testing of a duplicate liquid oxygen tank at Lewis (now Glenn) Research Center.

1999 October 1

Progress on the X-33 continues. Tank #2 was tested with liquid hydrogen. The tank was filled to 100% flight load and pressurized to 20 psi. The test was terminated early by the facility hydrogen leak detector sensors. Leaks are in process of being fixed.

Twenty-seven boxes of TPS panels have been delivered to date. This equates to 648 panels (52%) out of a total 0f 1241.

Engine #1 completed its chill tests. This was the second attempt at chilldown after fixing the facility hydrogen leak that occurred on the first attempt. The first turn-on for the ignition system is scheduled for this week.

Both vertical stabilizers are structurally complete. The right rudder is complete and installed on the vertical stabilizer and the left will be completed and installed this week. FADS plumbing on the forward ballast bulkhead are complete, less insulation.

The GPS antennas have passed qualification.

1999 October 15

Aerospike Engine #1 successfully completed its second ignition today. The third test is scheduled for next week.

Repair of liquid hydrogen tank #2 was completed this week. 34 major hydrogen leaks were identified while pressurizing the tank to 20 PSI with liquid hydrogen and during subsequent helium tests. Two low-pressure helium leak checks indicated that all leaks have been sealed. Lockheed Martin is testing woven "Y" components to determine the cause of the liner delamination on the flight tank. The Skunk Works is concerned that the liner may again have problems when testing resumes week. Meanwhile, tank #1 was delivered to the Skunk Works, Palmdale, California, today.

Installation of the Oceaneering thermal protection system tiles continues. The righthand body flap now has approximately 26 tiles bonded down, while the lefthand body flap is being prepared. The LOX area metallic TPS panels have been put in place for demonstration purposes. They will be removed to allow access for functional installations to be completed.

1999 October 29

Testing of the X-33 aerospike engines continued. Aerospike Engine No. 1 completed its 5.0-second duration tests and reached 80% power level. LOX injector post damage was discovered on 12 out of 3300 posts. This damage was repaired, and the post shutdown purge was increased to prevent LOX cooling and residual burning. The next test is scheduled to be a closed loop burn of over 20 seconds. Meanwhile, components of Aerospike Engine No. 2 were shipped to NASA Stennis, where buildup will start in the shuttle engine assembly building.

Liquid Hydrogen Tank #2 returned to testing at Marshall Space Flight Center the end of this week. Tank testing was delayed by the discovery of old ordnance when a water line was excavated for repair near the test stand being used. Tank tests on the subscale tank and woven "Y" components continue to test the current sealant. Ambient leak tests using gaseous helium have indicated that all leak areas have been repaired. On Tank #1, laser tracking of the tank and reference points to index all doubler templates has been completed. Lobe skins 2, 3, and 4 have been marked with doubler peripheries with Mylar templates. Lobe 1 had some residual engineering problems, which have been resolved.

The X-33 team is working toward powering up the vehicle on 23 November. The first of two low voltages PCAs arrived from Allied Signal, and the second is due to leave Toronto this week. The software for powering up the vehicle is going through test and integration. None of the recorded discrepancies appear to be significant.

1999 November 4

NASA Marshall Space Flight Center issued a Media Advisory reporting that: "Damage was discovered Wednesday [November 3] evening to one wall of the X-33's composite liquid hydrogen tank currently undergoing cryogenic and structural loads testing at NASA Marshall Space Flight Center in Huntsville, Ala. The damage was discovered at "approximately 6:45 p.m. CST while viewing the tank over video monitors, approximately two hours after the completion of a test cycle which appeared to be nominal." This was the fifth test being conducted on the tank. No one was hurt during the tank failure.

According to one report, the outer skin and honeycomb center apparently pulled away from the inner lining. Gene Austin, NASA's X-33 Program Manager, and his Lockheed Martin Skunk Works counterpart, Cleon Lacefield, went to Marshall late today (4 November) to survey the problem.

Lockheed may move to use an aluminum lithium tank design for the X-33. The schedule impacts will be addressed in the upcoming weeks. Already, even before this current damage occurred, program members were considering delaying the first X-33 flight, which is scheduled for July 2000. Dealing with the damaged composite tank may push the date of first flight into 2001.

1999 November 8

At today's meeting of Senior Staff and Center Directors held at NASA Headquarters, Ms. Griner of the Marshall Space Flight Center (MSFC) reported that: "The X-33 H2 [hydrogen] tank test team has been established and will be cochaired by MSFC and Lockheed since X-33 is a cooperative agreement."

NASA and Lockheed have set up a composite liquid hydrogen tank test failure investigation team. The team is responsible for finding the failure mechanism of the composite tank and consists of both NASA and Lockheed personnel. Both NASA and Lockheed Martin Skunk Works have reaffirmed their commitments to the X-33 program. The Skunk Works wants to understand the tank failure before making any decisions on an alternate tank approach.

1999 November 11

Congressman Dana Rohrabacher (R-Ca), Chairman of the House Space & Aeronautics Subcommittee, issued a statement on the damaged X-33 liquid hydrogen tank. "Saddened to hear" of the damage, Rohrabacher was "less hopeful about NASA's space transportation development efforts overall." "NASA's record of success has been poor by any measure," he stated. Rohrabacher vowed that, "When the 106th Congress returns for its second session, I will work closely with my colleagues from both parties in the House and Senate to pursue whatever bold ideas, painful reforms, and effective investments may be required to achieve our goals for American leadership in space transportation."

1999 November 11

Aerospike Engine #1 successfully completed a 10-second hot fire late today. The engine team is planning an 18-second hot fire late next week. That test will start with an open loop control system and transition to a closed loop control system.

1999 November 15

NASA announced the names of those making up the composite liquid hydrogen tank test failure investigation team. Leading the team will be Bob Goetz, senior advisor and former vice president of engineering for Lockheed Martin Skunk Works, and Bob Ryan, retired deputy director of the Structures and Dynamics Laboratory at the Marshall Space Flight Center. The NASA Media Advisory stated that other team members will be named shortly. [Bob Goetz requested that Paul Poitras (Lockheed Martin Materials Division Manager) and Bob Cuccias (Lockheed Martin Structures Division Manager) support the team, which has been coordinated with Mark Miller.] The investigation is expected to take four to six weeks. Parts of the failed composite liquid hydrogen tank were fabricated by Alliant TechSystems in Clearfield, Utah, and Lockheed Martin Skunk Works. A joint Lockheed Martin-Alliant team in Sunnyvale, Calif., completed the tank assembly. In the words of the NASA Media Advisory issued on this date: "Impact of the damage to the X-33 program is unknown at this time."

1999 November 17

In reporting on the damaged X-33 liquid hydrogen tank, Aerospace Daily speculated today that: "Now that the cause of the tank failure won't be fully understood until late this year, and repairs or rework to follow that before qualification testing can resume, it appears less likely than ever that the X-33 will be able to fly next year." NASA, however, states that the exact impact on the X-33 program schedule remains undetermined. [A joint Lockheed Martin Missiles and Space and Lockheed Skunk Works team has prepared a preliminary evaluation of the option to replace the composite hydrogen tanks with aluminum tanks. The schedule for this effort is 18 months, including testing. This plan will be briefed to Dr. Rogacki, Director of Space Transportation at Marshall Space Flight Center, this week.]

1999 November 22

Another hot-fire test of the X-33 linear aerospike engine took place at NASA'S Stennis Space Center today. The engine was pushed to 75% of full power during the 18-second closed-loop test.

1999 December 3

The composite liquid hydrogen tank test failure investigation team reconvened this week at NASA's Marshall Test Flight Center. A helium permeation test is scheduled on the lobes. The test consists of injecting 10-psi helium into one of the three pressure ports on each lobe to measure any migration through the honeycomb between the inner and outer skin panels. This is an attempt to understand the pressures measured in each of the lobes during the initial test series prior to the incident. Also the manhole covers will be removed from the top and bottom of the tank for visual inspection inside the tank.

1999 December 8

Progress on X-33 vehicle construction continues. Testing with the power on is continuing with software installed in both the vehicle and the portable operation control center. Current efforts are focused on bringing up the vehicle health monitoring computers. When these are operational, the basic foundation of avionics will be in place and will be ready for all other system checkouts to be run.

In addition, the righthand main landing gear wheel well structure and the associated aft righthand lower thermal protection system substructure have been mated in the main assembly tool. This is the first time that structure subassembled in three different tools came together with very minor problems. The Skunk Works also has installed three lower skins permanently on the righthand canted fin. When all skins (with the exception of the actuator bays) are installed, the Skunk Works will install the metallic thermal protection system panels on the lower (or windward) side of the canted fin. Installation of the righthand skin should be completed this week.

1999 December 15

At the request of the Lockheed Martin Board of Directors, the Skunk Works formed a combined technical Red Team to review both X-33 and VentureStar in late January 2000. Dr. Bill Ballhaus has agreed to lead the team. The team will be comprised of chief engineers from the government, Lockheed Martin, and venture contractors. The team will examine the technical viability and various issues involved with the X-33 Recovery Plan and will provide a SSTO credibility check for the VentureStar design.

As for the Recovery Plan itself, Skunk Works X-33 officials met with their NASA counterparts last week. NASA agreed to give the Skunk Works written authorization to continue on with the design of the metallic (aluminum-lithium alloy) tanks this week. They also agreed to increase the program obligated funding level by $32M.

In addition, a three-man Skunk Works team went to Huntsville to assist NASA in extracting the hydrogen tank from the test fixture, which was successfully completed on Saturday, December 11. The investigation team has indicated that they may want some additional support to remove all or a portion of the failed lobe for analysis.

The Skunk Works removed two actuator controllers from valve assemblies supplied by Lockheed Martin Missiles and Space division. These in turn were shipped to Stennis to allow aerospike engine testing to continue. The controllers have proved unreliable, and Rocketdyne has had failures of the units allocated to them plus their spares. The controllers were supplied by Allied Signal, which is working with their supplier to remedy the situation.

1999 December 16

Following today's meeting between NASA Administrator Dan Goldin and Vance Coffman, Lockheed Chairman of the Board, NASA gave the Skunk Works approval to implement their X-33 recovery plan. Marshall Space Flight Center gave Lockheed written authorization to continue with the design of the metallic liquid hydrogen tanks, and appears to have agreed to increase the X-33 program obligated funding level by $32 million.

1999 December 18

Engineers at NASA's Stennis Space Center ran the Rocketdyne XRS-2000 X-33 to full power for the first time today, Saturday, hitting 100% thrust in an 18-second-long hot-fire test at Stennis' A-1 test facility. Engine performance was deemed "satisfactory" throughout the test, based on preliminary data. Minor pinhole-sized erosion discovered on the interior wall of one of the engine's 20 thrust cells was considered within bounds for development testing and was not believed to be a block to additional hot-fire tests. The thrust cells direct the engine's exhaust onto actively cooled "ramps" that allow the plume to expand to the optimum angle for its altitude during ascent. X-33 engine testing will resume early next year.