Recently, the Starline manned spacecraft developed by Boeing Company of the United States docked with the International Space Station, which is the second unmanned orbit test flight mission of "Starline". After docking at the International Space Station for 5 days, the spacecraft successfully returned and landed at the White Sands Missile Range in New Mexico, USA. So, what are the characteristics of the "Starline"? What twists and turns has the spaceship experienced in its development?
During the first flight, "rollover" and try again are called off
Starline, formerly known as CST-100, is a partially reusable manned spacecraft designed to transport astronauts to the International Space Station and return safely. The spaceship consists of a reusable manned module and a disposable service module. The launch weight is 13 tons, the height is 5 meters, and the diameter of 4.5 meters is slightly larger than that of the manned dragon spaceship of SpaceX Company in service, but less than the diameter of 5 meters of the Orion manned spaceship that is about to fly for the first time.
The pressurized space inside the spaceship is 11 cubic meters, which can accommodate up to 7 astronauts. The spaceship adopts a self escape design and is equipped with a liquid escape engine. It can land on land through an air bag. The return capsule can be reused for 10 times. It is designed to be compatible with multiple rockets for launch.
Normally, the test flight of a new type of manned spacecraft should have been the focus of media attention, but Boeing was unusually low-key in this launch mission, and neither NASA nor media reports were hot. This strange phenomenon began with the failure of the test flight more than two years ago.
In December 2019, the first unmanned orbit test flight mission of "Starline" was carried out, and everything was normal before the separation of ship and arrow. Subsequently, a task timer on the spacecraft failed, making the spacecraft failed to complete the orbital maneuver after the separation of the ship and arrow as planned.
This failure consumed a large amount of propellant of the spacecraft, resulting in the remaining propellant unable to meet the conditions for its safe docking with the International Space Station, so the docking mission had to be canceled, allowing the spacecraft to return to the Earth in advance.
After investigation, it was found that an error time point was set when the timer was initialized, which resulted in 11 hours of timing deviation.
During the subsequent in orbit inspection, the Boeing research team found another "valve mapping error" of the spacecraft, which involved the engine in the spacecraft service module. Fortunately, this error was found before the spaceship returned, otherwise, it may cause the service module to separate from the return module and fly forward again and hit the return module, with unimaginable consequences. After discovery, the development team carried out emergency troubleshooting and sent the modified flight control code to the spacecraft about 3 hours before landing.
After the "rollover" of the first test flight of "Starline", in addition to a large number of rectification opinions, NASA also required Boeing to conduct another unmanned test flight for safety reasons before carrying out manned flight. Although Boeing initially complained about this, with the deepening of the investigation and the exposure of the problems, it finally had to accept the reality and pay $410 million for the second unmanned orbit test flight.
In August 2021, after more than a year of software review and rectification, the "Starline" was pushed to the launch pad again to perform the second orbital test flight mission. However, during the pre launch inspection, the development team found that 13 propellant valves of the spacecraft were jammed and could not be opened. Fortunately, it was discovered before the launch, otherwise the spaceship would probably fall directly into the atmosphere after launch.
After the problem was found, the launch mission of the spaceship was immediately canceled, and it was pulled back to Boeing, which opened a long road to "zero" again.
Should have been a "mainstay" instead of a "spare tire"
A test flight failure and an emergency call for a halt have made Boeing lose face in the development of manned spacecraft, and its early rhetoric has almost become a laughing stock in the industry. The most dramatic thing is that in the original "double insurance" plan of NASA, Boeing is the mainstay of the manned space program, while SpaceX is only the "spare tire". Now the "spare tire" has been successfully repaired, and Boeing, the "mainstay", has just successfully test flown.
In fact, as early as 2010, before the retirement of the space shuttle, NASA began to look for contractors for new manned spacecraft. At that time, Boeing, Blue Origin, Sierra Nevada, SpaceX and other companies were on the observation funding list.
Based on the successful experience of the previous "Commercial Freight Service Plan", NASA proposed the "Commercial Manned Spaceflight" project. It plans to fund two enterprises to develop manned spacecraft at the same time, replacing the space shuttle that was about to retire at that time, and getting rid of the dependence on the Russian Soyuz manned spacecraft.
After four years of evaluation, NASA officially announced in 2014 that Boeing and SpaceX were selected. The former's spaceship was named "Starline", with a total funding of 5 billion dollars; The latter's spaceship is a "manned dragon", with a total funding of 3.2 billion US dollars.
In March 2019, after five years of development, the two companies took the lead in successfully carrying out the first unmanned test flight mission. Nine months later, Boeing's "Starline", known as the "century old shop", also carried out an unmanned test flight mission. As mentioned above, this mission failed, and the spacecraft almost could not return to Earth.
After two years of rectification, Boeing finally began its second unmanned test flight. However, at this time, the manned dragon spacecraft has successfully completed seven missions into orbit, six of which were manned flights.
Even if Boeing successfully completed the subsequent test flight, "Starline" has fallen far behind SpaceX in terms of progress and cost, which has led the whole project into a vicious circle. The slower the progress is, the higher the cost of a single seat will be, and the higher the quotation of astronauts/tourists for taking the spaceship into space will be.
The media generally believe that "Starline" is difficult to achieve success in the pure commercial and space tourism market in the short term. In addition to the high cost, a series of accidents have also caused tourists to worry about the safety of the spacecraft.
The supplier's business trip is not good
In recent years, Boeing has repeatedly encountered quality, schedule and funding problems in various major projects, which are also reflected in the company's commitment to the NASA "Space Launch System" project. The reasons are diverse, but unreliable suppliers cannot escape the blame.
Boeing's projects mostly adopt the traditional general contracting+procurement mode, with low vertical integration, and a large number of subsystems and key components come from outsourcing. Boeing also lacks effective quality and cost control over suppliers, resulting in uneven product quality, frequent problems and high quotations from suppliers. The most troublesome thing is that the coordination problem between the supply and demand parties further led to the slow progress of the project.
This is precisely the case with the valve trap of the "Starline". Recently, Boeing Company admitted in a statement for the first time that it finally decided to redesign the valve system of the spacecraft in order to completely solve the jam problem.
Boeing and NASA agree that the valve jamming is mainly caused by chemical reaction between normal temperature propellant and aluminum materials, coupled with wet air in the launch site and water intrusion into the valve. It was reported that the valve supplier Rockdyne objected to this. They accused Boeing of using a special chemical cleaner in the ground test of the spaceship, but Boeing countered that it was not true, and also accused Rockdyne of not meeting the contract requirements in design and not leaving enough design margin for the propulsion system to resist chemical reactions.
The most important thing is that during the nine month test, Boeing did not completely reproduce the jamming fault of the spacecraft valve, but constantly measured and ensured that the valve had sufficient opening, which is called to let the spacecraft return to the launch pad as soon as possible.
Due to the continuous delay of the test flight progress of the "Starline", the second orbital test flight can only be carried out using this temporary remedial plan. However, the patching scheme is ultimately to cure the symptoms rather than the root cause. In the orbit entry maneuver of this test flight, only one second after the spacecraft ignited, one engine failed to shut down, and only 25 seconds after the standby engine started by the flight control system was shut down for unknown reasons. Fortunately, the spacecraft started another group of engines for maneuver, and finally completed the orbit entry.
This kind of engine is equipped with four groups on the side wall of the service cabin, each group is equipped with three backward facing engines (pushing forward), which are redundant to each other. In general, even if the subsequent "Starline" test flights are completed, the commercial prospects are not optimistic.
Indeed, the introduction of the manned space tourism mission of the manned dragon spacecraft has been reported frequently. The latest mission has been scheduled to 2024, while the space tourism mission and quotation of the "Starline" have not been reported by any media. Commercial manned spacecraft without commercial tourism business, coupled with rising costs, "Starline" project has become a chicken rib for Boeing - the more we work, the more we lose.
author /Tian Feng
Source: China Aerospace News
