NASA's James Webb Space Telescope takes off from French Guiana on the northeast coast of South America and rides a European Ariane rocket into the Christmas morning sky.
That means the world's largest and strongest space telescopes will set off to observe the light emitted by the first stars and galaxies and search the universe for signs of life.
Thomas Zurbuchen, nasa's science mission leader, said, "What a great Christmas present. ”
Preview: The Next Generation of Space Telescopes
Forward-looking is an important way of thinking to promote the development of human society. Long before the Hubble Space Telescope was launched, scientists were already imagining the future — what would the next generation of space telescopes look like after Hubble's retirement?
In September 1989, six months before Hubble launch, the American Space Telescope Research Institute (STScI) and NASA brought together more than 130 astronomers and engineers to co-host the Next Generation Space Telescope symposium. The conference examined the feasibility of building a 10-meter aperture near-infrared telescope in high Earth orbit or a 16-meter aperture telescope on the lunar surface in 2005. After Hubble's launch, scientists found that Hubble's ability was still limited, and it could not see the mid-infrared band image of the first 500 million years of the universe' birth. In 1996, a committee led by astronomer Alan Dressler formally proposed to NASA an infrared space telescope to make up for Hubble's shortcomings, designed to see the "first rays of dawn" of the universe 13 billion years ago.
Daniel Goldin, then director of NASA, was very interested in this, and after preliminary research they determined the technical indicators of the "next generation of space telescopes": the diameter of the main mirror is 8 meters, the mirror material is lightweight metal beryllium, the operating temperature is as low as -223 °C, and the working orbit is located at L2 point of Theragian Lagrange, these initial design indicators are almost exactly the same as the webber telescope that is now complete.
Astronomers have also questioned such radical design metrics, which can lead to extremely high research and development costs. At the same time, Daniel Golding pursued a "faster, better, cheaper" development strategy in his tenure as NASA's director, accomplishing some of the more inspiring tasks at a faster manufacturing speed and lower manufacturing costs. Under this strategic approach to leadership, the cost of the Next Generation Space Telescope was estimated to be only about $500 million, and the launch time was expected to be 2007 to 2011, which was acceptable at the time.
At first, the strategy seemed to work: the Mars Pathfinder mission in 1997 and the Lunar Explorer mission in 1998 were both very successful. However, in 1999, as soon as the wide-area infrared probe was launched, the refrigerant carried by it was leaked out due to low-level errors, and the probe was close to scrapping; the two Mars missions, the Mars Climate Probe and the Mars Polar Lander, also caused catastrophic losses due to low-level errors, and the particles were not recovered. Facts have proved that "faster, cheaper" can not be "better" at the same time, serious, thoughtful and meticulous, safe and reliable, foolproof is the attitude that the aerospace field should have.
Since then, NASA has strictly constrained the manufacturing process of the detector to ensure that the mission will not go wrong, and the cost will increase. This strategic shift has raised the cost of the Weber telescope to more than $1 billion, and the diameter of the main mirror has also been reduced from 8 meters to 6.5 meters to reduce costs. In addition, additional tests have shown that it seems unlikely that the telescope will be launched by 2011.
At this time, people have not yet realized the seriousness and complexity of the matter: more powerful telescopes require higher quality control, higher quality control brings higher costs, and higher costs determine that the performance of this telescope must be more powerful - they have fallen into a "dead cycle".
A new century, a new hope
People ushered in the new 21st century with enthusiasm. In 2002, the "New Generation Space Telescope" was named after NASA's second director, James Webb, who led NASA to achieve the feat of Apollo manned moon landing. Since then, the whole world has been waiting for this huge space telescope called "James Webb" to take off.
In the first few years of the new century, the telescope team has been arguing for the viability of the Weber telescope. To increase the resolution of the telescope, they designed a huge foldable main mirror; to reduce the temperature, they designed a huge heat shield that was about the size of a tennis court but as thin as a hair; and to produce higher-quality observations, they designed four extremely advanced infrared lenses or spectrometer payloads. In 2004, the telescope's most difficult and demanding core components began pre-production, including 18 main mirrors and four scientific payloads, at an expected cost of about $1.6 billion.
In 2005, NASA and ESA reached an agreement to launch the Webb Telescope using an ESA Ariane 5 rocket. In 2007, most of the core design of the entire Weber telescope passed the preliminary review, marking the official beginning of the detailed design, procurement, assembly and testing of the Weber telescope. However, the difficulty of making the Weber telescope is still underestimated, and its actual cost is much more than the webb telescope's budget. During this early technical demonstration session alone, the Weber telescope burned $2 billion, and additional testing sessions delayed launch to 2014.
resuscitation
The cost and test time issues in the process of task advancement are gradually becoming prominent. In November 2010, new statistics showed that the total cost of the Weber telescope had grown to $5 billion, launch no earlier than September 2015, more than a year later than planned. The journal Nature refers to the Webb telescope as a "telescope that devours astronomy" because its huge expenses have affected the funding of other astrophysical research missions.
In July 2011, members of Congress voted to cut NASA's 2012 budget by $1.9 billion to cancel the Weber telescope program — at a time when its total cost soared to $6.5 billion and launch was delayed until 2018. Congress blamed NASA's soaring costs not for technical problems, but for misguided management. This is the biggest challenge that the entire Weber telescope has faced since it was planned, has it been more than ten years of preliminary demonstration, has the basic design of the main mirror and scientific payload been completed, and the billions of dollars that have been invested have been wasted?
Politicians see the Weber telescope as a meaningless bottomless pit of money burning, but scientists with ideals still regard it as a treasure, and they really can't bear to give up Weber, the most powerful space telescope in history. After some mediation, in November 2011, NASA and the House of Representatives reached an agreement: the House of Representatives' proposal to cancel the Weber Telescope program was canceled, but the price of the compromise was that the program's spending could only be limited to less than $8 billion. NASA said it would delay other plans, such as scaling back spending on the development of commercial manned spacecraft, to ensure the telescope launched in 2018.
There is no Plan B
The Construction Process of the Weber Telescope must ensure both high performance and high quality. The Hubble Space Telescope operates in a low-Earth orbit at a height of 600 km, and if there is a fault, astronauts can be sent to repair it, while the Weber Space Telescope will operate at L2 point of Theragranges, which is 1.5 million kilometers away from Earth, and once it fails after launch, it will be an irreparable loss, and there is no plan B as a retreat.
As a result, the individual devices of the Weber telescope are produced to extremely high standards and tested under extremely harsh conditions. In 2011, the first hexagonal main mirror was produced, which took a total of six years. The quality control requirements of the main mirror are extremely high, and the maximum undulation that can be allowed for each hexagonal main mirror is only 25 nanometers, and if this lens is enlarged to the size of the moon, its maximum undulation will not exceed 8 centimeters.
From 2012 to 2014, the four scientific payloads were produced sequentially, assembled into the Integrated Scientific Instrument Module (ISIM) and entered the testing process, and several cryogenic tests and vacuum tests were carried out in the Goddard Space Environment Simulator. In 2015, all 18 hexagonal lenses of the main lens were completed. At the end of 2016, the main structure of the entire telescope was completed, followed by a long testing process of vibration and low temperature. In 2017, the Optical Telescope Module as a whole underwent cryogenic tests for up to 100 days to ensure that all of its systems would function properly in similar space environments.
Tough testing on the ground is indeed beneficial. In March 2018, the webb telescope's heat shield tore apart during testing, and NASA had to further delay the launch program for at least 3 months. In April of that year, further vibration tests on the heat shield showed that the heat shield produced twice as much vibration as expected, and after the test, 20 of the 1,000 screws were found to be loose. At the same time, the careless staff also caused unnecessary trouble, using the wrong solvent when cleaning the telescope, and also miswiring caused the telescope to withstand too high a voltage.
All told, loose screws, misuse of solvents, and miswire connections delayed the Launch of the Webb telescope by a further 1.5 years and burned an additional $600 million in testing dollars. NASA had to come forward to explain that the $8 billion was certainly not enough, and the promise of a 2018 launch would no longer be fulfilled — the launch date was again postponed to May 2020.
The atmosphere was tense again, and a 2018 review showed that the Webb telescope could have 344 different malfunctions — a frightening number for any space mission. Grant Tremblay, an astrophysicist at Harvard University, says that means if a metal pillar fails, or if a cable gets stuck, "we get a $10 billion worth of waste paper." According to this review report, NASA conducted a systematic investigation and test of the Weber telescope, and controlled the total cost of the telescope to $8.8 billion, and the launch time was further postponed to March 30, 2021.
Covid-19 is raging and piracy is rampant
Just as NASA began to troubleshoot all possible failures, it caught up with the new crown pneumonia pandemic that was raging around the world. In response to centers for disease control and prevention policy, in March 2020 NASA had to suspend several key testing efforts for the Weber telescope. At the same time, NASA has also experienced a shortage of manpower, and they can only focus on the 2020 Perseverance rover mission. In this way, Weber's launch date was postponed to October 31, 2021.
NASA struggled to complete the last few tasks before the launch of the Weber telescope under the influence of the epidemic, and successfully carried out the final folding and packing work. However, its launch was again postponed until at least the end of November 2021 for three other reasons, this time independent of the telescope itself.
First, the problem is with the rocket. In August 2020, when Ariane 5 was on a mission to launch two communication satellites, staff found that the fairing of the rocket was abnormal, and the separation did not appear to be complete. In addition, in the February 2020 launch mission, the vibrations caused by the flight were higher than normal. This all poses a potential threat to Weber's launch. NASA postponed launch until at least the end of November 2021 and asked Ariane to address the above issues through a redesign. ESA successfully launched two improved Ariane 5 rockets on July 31 and October 24, 2021, prior to the Webb launch, and the two launches proved that the problem was solved.
Secondly, the epidemic situation at the Koulu Cosmodrome is not optimistic. French Guiana has not yet been widely vaccinated, and if the situation worsens further, it could delay the preparation of the Weber telescope at the launch site.
Finally, since the launch site is located in South America, it takes 16 days to transport the telescope from the United States to the launch site, and there is one biggest threat waiting for them - pirates. Pirates probably won't ignore this $10 billion piece of fat, which is likely to hijack the transport ship. This is not out of thin air, as early as 1982 a telescope called JCMT was hijacked on its way to the UK. In response to this, NASA remained silent about Weber's specific date of transportation, and called the U.S. Navy to escort him. The Weber telescope finally arrived safely at the Kuru Space Center in French Guiana on October 18, 2021, with a launch date set for December 18, 2021.
A crow never the whiter for washing herself often
Weber's preparations at the Kuru Space Center were relatively smooth, and it was thought that the telescope was finally able to punctualize once and launched on December 18, 2021. However, the staff of Ariane Company caused trouble again, causing the Webb telescope on the string to postpone the launch again.
When the staff connected the Weber telescope to the launch vehicle adapter, the clamp that fixed Webb to the launch vehicle adapter suddenly and unexpectedly released, causing the entire telescope to shake a lot. NASA immediately investigated and conducted additional tests on the Webb telescope to prevent damage to the telescope from this vicious event.
Thankfully, the shock was tested to have no damaging effects. Weber's launch date was only postponed by four days, the fuel refueling work was carried out normally, and the launch time was reset to 20:20 Beijing time on December 22, 2021.
However, in the eyes of great anticipation around the world, the "Ace Pigeon" was postponed again – on December 15, a week before the original launch date, the ESA said that the launch would be postponed again – citing the need to solve the communication problem between the telescope and the rocket, and the launch time was once again reset to XX:00 on December 24, 2021. By the 22nd, the launch site staff found that the weather at the launch site was really bad, and the vertical transfer of the rocket could not be carried out, and the launch time was postponed by 24 hours, aiming at 20:20 on December 25, the Christmas Day in the West.
On the 24th, the weather at the launch site was good, and the rocket finally launched the assembly plant, walked through the last part of the road on the ground, went to the launch pad to refuel, and waited for the launch.
When the "Ace Pigeon" telescope of more than ten years finally delayed repeatedly before launching, he did not forget the title of "Ace Pigeon", which he had been loyal to for half his life, which was really difficult to move.
Twenty years of grinding a mirror, the frost blade has not been tried. Who has anything wrong with the king today? Many of the engineers and scientists involved in the construction of the Weber telescope took over this great task in their prime, and now they are gray-haired. Now they can finally watch this telescope that has devoted half their lives to the sky, taking people around the world to see the first rays of the universe.
Author: Academic Department of the Blue Sky Society, Source: Peking University Youth Astronomical Society, original title: "A History of The Delayed Heartbreak Launch of the "Ace Pigeon" James Weber Space Telescope"