What pitfalls might a “star” fall into on his journey?

After a flight of 10 minutes or more, the launch vehicle accurately puts the spacecraft into the predetermined orbit, but this does not mean that the journey will be smooth. Most geostationary orbit satellites are not sent directly into the geostationary orbit, but need to enter the predetermined orbit through self-ascending; and deep space spacecraft also need to use their own engines to change their orbits before going to their destination, which is much more complicated than the launch vehicle system.

These high-mass, high-value payloads have a design life of at least 2 to 3 years and need to withstand the harsh deep space environment. They may experience various failures in orbit. Some satellites are permanently scrapped in transfer orbits, while others use multiple means such as system restart, subsystem redundancy, and orbit reconstruction to tenaciously enter the working orbit. Although a failed satellite cannot achieve its expected lifespan, losing a certain amount of lifespan is always more valuable than being completely scrapped.

Radar antenna not deployed

As the first generation of strategic synthetic aperture radar (SAR) reconnaissance satellites in the United States, LACROSSE is a mysterious satellite. However, its real name is not "Lacrosse", but "ONYX". The advantage of synthetic aperture radar satellites is that they can penetrate clouds and water. Compared with optical reconnaissance satellites, they can ignore the obstruction of clouds and obtain a high resolution.

A total of five Onyx synthetic aperture radar satellites have been launched, deployed in 57-degree orbits and 68-degree orbits. The first three satellites are the first generation, using X-band imaging; the last two satellites are the second generation, using X/L dual-band imaging. The Onyx satellite is said to be numbered 3100, with a launch mass of 14,500 kg to 16,000 kg. The Onyx satellite is equipped with a huge side-mounted umbrella antenna for radar imaging, with a ground resolution of about 0.3 meters. It is equipped with two huge solar panels with a length of 45 meters, which provide the satellite with an average of 20 kilowatts of terrifying power. Martin Marietta (the predecessor of Lockheed Martin) is the main contractor for the development of the satellite.

A reference diagram of an onyx-like configuration from a USAF document

The first Onyx satellite was launched on December 2, 1988, aboard the Atlantis space shuttle, with the mission number STS-27. The satellite was deployed in an orbit with a perigee of 437 km, an apogee of 447 km, and an inclination of 57 degrees, and was numbered USA34.

The only declassified synthetic aperture radar satellite image of Onyx

Onyx-1 had a number of problems, including the failure of its parachute antenna to deploy. In a 2001 interview, Gibson, an astronaut on the STS-27 mission, recalled: "We released the satellite, but the satellite had a lot of problems, and we re-entered the satellite, captured it and repaired it." However, NASA has not confirmed whether the STS-27 mission involved a secret spacewalk.

Anyway, the first Onyx satellite was deployed. However, the satellite's lifespan did not meet expectations. It left orbit in 1997 after a lifespan of more than eight years. The second Onyx satellite was in orbit for 20 years and left orbit in March 2011. The next four Onyx satellites were launched by Titan 4(03)B rockets.

High gain antenna umbrella bolt stuck

As a flagship deep space exploration mission, the Galileo Jupiter probe is also one of the probes with the most program revisions in NASA's history.

Initially, Galileo was planned to be launched using a space shuttle and a three-stage inertial upper stage, but the thrust was still insufficient and a Mars flyby was needed to obtain sufficient energy. Moreover, the mission was postponed to 1984 due to the delay of the first flight of the space shuttle. The gravity acceleration effect of the Mars flyby was greatly reduced, and the carrying capacity of the space shuttle itself was also lower than expected. NASA once decided to split the spacecraft into two parts for launch.

Fortunately, the development of the Centaur G cryogenic upper stage for the space shuttle began. The powerful Centaur G upper stage was able to carry Galileo directly into the Earth-Jupiter transfer orbit after it separated from the shuttle cargo bay. However, the Centaur G upper stage itself was questioned, and the explosion of the Challenger space shuttle was the fatal blow that declared its death. In June 1986, NASA ordered the Centaur G upper stage to be cancelled. A two-stage inertial upper stage did not have the ability to transfer directly to Jupiter, so it was changed to a gravity assist sequence of Earth-Venus-Earth-Earth-Jupiter. The spacecraft was designed to fly directly to Jupiter, but the new gravity assist would bring the spacecraft closer to the sun than planned, causing the originally planned thermal control system to not meet the new flight sequence. In order to avoid overheating and damage to the high-gain antenna, the antenna was changed from the original plan to be deployed after launch to the original design temperature control conditions after the boost flight.

At 16:45 UTC on October 18, 1989, the Atlantis space shuttle took off, and the final inertial upper stage sent Galileo into a heliocentric orbit with a perihelion of 0.67 AU and an aphelion of 1 AU.

During its first flight of 14 months, Galileo encountered no major problems. On December 19, 1990, the first Earth gravity assist was carried out as planned, and on April 11, 1991, the high-gain antenna was deployed under the set conditions. The 18 ribs of Galileo's high-gain antenna are deployed by a pair of motors driving a series of push rods, ball screws and support rings. However, only 13 of them were successfully deployed, and the other 5 were stuck in the bracket structure. Two of them were later released, while the adjacent 3 ribs remained in place, and as they were driven, the ball screw gradually twisted, and finally the drive mechanism was completely stuck. The ball screw needs to move 8.6 cm to deploy the antenna, but it actually only moved 1.5 cm.

The problem was soon found. The coating of the connection point between the Galileo bolt and the socket was damaged due to long-term excessive stress. During the years of manufacturing and storage of Galileo, the lubricant was lost, and the only time the lubricant was applied was 10 years after the launch! The bolt and the socket finally produced a cold weld under vacuum and strong pressure. In other words, the bolt was "welded" to the socket by pressure and became a whole. Fearing problems during ground testing, the antenna was delayed because there was no backup, and the antenna was not fully tested! Finally, NASA decided to use thermal stress and centrifugal force to pry open the bolt, and "hammer" the bolt through motor drive or thruster ignition.

Galileo with its high-gain antenna deployed, but unfortunately it was not implemented during the mission

In April 1992, Galileo reached perihelion again. The spacecraft was facing away from the sun, leaving the high-gain antenna in the shadow for 50 hours, but the latch still did not deploy. According to the simulation, 6 to 12 hot and cold cycles are required to deploy the antenna, but the assumptions on which it is based may also be wrong. The low-gain antenna was retracted 6 times, and attempts were made to shake the latch with the help of the shaking caused by the emergency stop, but it was useless. In September 1992, 7 hot and cold cycles still failed to deploy the high-gain antenna. But each cycle wastes 4 kilograms of propellant, and there is not so much propellant to waste.

As an alternative, Galileo used thrusters to ignite the antenna motors to move. Each ignition could cause the ball screw to turn a partial angle, thereby increasing the driving force. At the same time, the thermal stress of the antenna tower would reach its maximum near perihelion. It was believed that "hammering" the ball screw at this time could release a rib. If the high-gain antenna was not deployed by March 1993, the high-gain antenna would be abandoned and all low-gain antennas would be used for downlink. Combined with the upgrade of the Deep Space Network and the compression algorithm, the rate can reach 100 times the original plan.

From December 29, 1992 to January 19, 1993, Galileo conducted more than 15,000 "hammering" operations, but the ribs that were opened only opened a little wider, and the ribs that were not opened remained closed. In March, Galileo began to accelerate its spin to 10.5 revolutions per minute, but the high-gain antenna remained unmoved, and NASA finally announced that it would abandon the high-gain antenna.

Instrument failure/receiver failure

The VGR-77 mission was the most spectacular and greatest expedition in human history. The 1977 Grand Tour window gave the spacecraft the opportunity to fly by four outer planets at once. At 14:29 UTC on August 20, 1977, less than five minutes after a delay, the Voyager 2 probe set out on its deep space exploration journey. The spacecraft entered a heliocentric orbit with a perihelion of 1 AU and an aphelion of 6.28 AU. A few hours after launch, a series of structures began to deploy, but no signal was received that the scanning platform boom was deployed. The star sensor was disturbed by some insulating debris floating near the spacecraft, and the backup attitude control system was mistakenly activated during the stabilization process. New software was urgently developed and tested on the ground and injected into the probe. The boom was then determined to be within 0.5 degrees of the lock position based on the star sensor image, and the mission control center successfully locked it by shaking the spacecraft.

Diagram of the Grand Tour

On August 30, Voyager 2 began its first orbital correction, but found that the thrust of the thrusters was far lower than expected. Analysis showed that part of the gas flow was blocked by the instruments of the spacecraft, resulting in insufficient effective thrust. According to this progress, Voyager 2 can only barely reach Saturn. The mission control center optimized the maneuvering process of Voyager 2, advancing the time of Saturn's flyby from 70 days after Jupiter's flyby to the perigee, and at the same time changed the star sensor of Voyager 2 from "Canopus" to "Deniben" to reduce the impact of solar light pressure.

On September 5, 1977, Voyager 1 entered a heliocentric orbit with a perihelion of 1.01 AU and an aphelion of 8.99 AU. On February 23, 1978, Voyager 1 conducted a scanning platform test, and the scanning platform's deployment actuator got stuck, which was a devastating blow to subsequent missions. After testing the ground prototype, the Jet Propulsion Laboratory of the United States ordered Voyager 1 to test it again. On May 31, the actuator did not get stuck again. The reason for the last jam may be that the gears of the actuator were contaminated by dust, causing the gears to get stuck. In subsequent tests, the dust was crushed or removed, and the platform resumed normal operation.

Voyager 1 and Star-37 solid rocket engine

Here comes something more interesting. When the Jet Propulsion Laboratory of the United States was focusing on Voyager 1, they forgot about Voyager 2. Voyager 2 automatically entered the "command failure warning" on April 5, 1978. When the main receiver did not receive the ground uplink command within a week, it was assumed that the main receiver failed and switched to the backup receiver. However, the backup receiver could not lock the signal from the ground because the Doppler shift caused by the rotation of the earth and the flight of the spacecraft would cause the signal frequency to change. The engineers did not pay attention to this problem because they would switch back to the main receiver after 12 hours. However, the main receiver encountered a short circuit just 30 minutes after it was turned on and completely failed.

This is a big problem. If humans want to know the secrets of Uranus and Neptune, then hope must be placed on the backup receiver of Voyager 2. Another 7 days passed, and the spacecraft switched to the backup receiver again. At this time, the computer-controlled oscillator developed by the Deep Space Network came in handy.

On April 13, these variable-frequency signals were successfully uplinked to Voyager 2. But not every command was successfully received? Engineers found that the acceptable frequency band of the receiver changes with temperature. This variable-frequency uplink signal is not an easy task - the Doppler shift caused by the rotation of the earth alone is 30 times the acceptable frequency range of Voyager 2, and every error must be taken into account. The Jet Propulsion Laboratory in the United States has established a detailed thermal model of each subsystem of Voyager 2, which can accurately predict the receiver temperature with an error of within 0.1°C. But even so, communications are still intermittent. In October, the problem was solved, and the mission control center injected the detection sequence command into the spacecraft. Even if the signal is completely interrupted in the future, Voyager 2 can complete the rendezvous with Jupiter and Saturn autonomously.

This was not the end of the problem. On September 7, 1979, Voyager 2 arrived at Jupiter. The strong radiation from Jupiter caused unpredictable changes in the receiver frequency band. After the Earth occultation zone, the Deep Space Network had to use multiple different frequencies to uplink in the hope that Voyager 2 could just "hear" the command.

Despite a series of problems, the Voyagers are still one of the greatest and most successful planetary exploration projects in human history. A series of failures were well resolved after the Saturn flyby, and the response measures were also perfect. The two Voyagers continued to fly into deep space and continued their journey of outer space exploration.

Apogee engine failure

Advanced Extremely High Frequency Strategic Broadband Communications Satellite, also known as the "Military Star 3" communications satellite. Advanced Extremely High Frequency Satellite can provide theater commanders with highly secure, anti-interference, and difficult-to-intercept communications services, and can meet tactical communications needs such as real-time images, battlefield maps, and tracking data transmission. It will become the backbone of the US Department of Defense in the mid-term stage of military satellite communications architecture. It is built on the A2100M platform and cost more than $580 million.

Advanced Extremely High Frequency Strategic Broadband Communications Satellite

On August 14, 2010, the Atlas 5-531 launch vehicle successfully launched the 6,168 kg Advanced EHF-1 communications satellite into a supersynchronous transfer orbit with a perigee of 225 km, an apogee of 50,212 km and an inclination of 22.2 degrees. According to the plan, the apogee engine was first started, and the apogee was raised to an orbit of 19,000 km and an inclination of 6 degrees through 30 days of maneuvers, and then its Hall thrusters were used to work for 90 days to enter the geostationary orbit. The satellite has a design life of 14 years. The satellite's main power system uses the BT-4 type hydrazine-nitrogen tetroxide 450N thruster manufactured by Ishikawajima-Harima Heavy Industries, and also has 6 22N monopropellant thrusters and 12 0.9N monopropellant thrusters developed by Aerojet. The BPT-4000 dual-mode electric propulsion system uses a high thrust mode in the transfer orbit and a low thrust and high specific impulse mode when maintaining the orbit.

The Advanced Extremely High Frequency Satellite in the fairing, note the side-mounted electric thrusters installed on the waist

However, during its first apogee maneuver, the thruster failed to work properly and automatically shut down. The second attempt two days later also failed. This means that the apogee engine has been scrapped. From 7:00 on August 29, the "AEHF-1" switched to the mode of using the 22N monopropellant thruster to raise the orbit, and the electric propulsion will take over the orbit transfer in advance.

In the first stage, three 22N thrusters worked until September 7, raising the apogee to 1,156 kilometers and an inclination of 19.9 degrees. Then six 22N thrusters worked simultaneously until September 22, raising the perigee to 4,712 kilometers and an inclination of 15 degrees. In the third stage, the electric thrusters were turned on and used for 10 months to raise the apogee to the geostationary orbit. Finally, it entered the planned orbit on October 24, 2011, and was able to meet its 14-year life requirement.

Apogee engine failure

The Mobile User Objective System is the same unlucky fellow as the Advanced Extremely High Frequency-1. It also uses the A2100 platform and was also pitted by the BT-4. The Mobile User Objective System tactical narrowband communications satellite will provide 10 times the transmission capacity of the BT-HF successor satellite system and will provide a more reliable communication method for the US military. The first satellite of the Mobile User Objective System was launched in 2012. The constellation plans to build 4 operational satellites and 1 backup satellite.

Layout of the Mobile User Objective System constellation

On June 24, 2016, the Atlas 5-551 launch vehicle successfully launched the 6,740 kg MUOS-5 communications satellite into a high perigee synchronous transfer orbit with a perigee of 3,838 km and an inclination of 19 degrees, but then its Ishikawajima-Harima Heavy Industries BT-4 apogee engine failed to ignite normally. MUOS-5 ignited 26 times with its 22-N monopropellant thruster and completed the final orbit raising on November 3. However, the MUOS-5's north-south position-keeping ability is obviously limited. Compared with the first four MUOS satellites that maintained an inclination of 2.5 degrees, the inclination of MUOS-5 reached about 6.5 degrees, and the eccentricity of its orbit is also much greater than that of the other four satellites.

Solar panel failure

"Intelsat 19" is a high-throughput communications satellite ordered by Intelsat Corporation from Space Loral. It is built on the SSL-1300 platform with a launch mass of 5,600 kg. It was launched on June 1, 2012 by the Zenit 3SL carrier rocket to replace "Intelsat 8" with a design life of 18 years.

Zenit 3SL launches Intelsat 19

Intelsat-19 announced later in the day that the satellite's south solar panels could not be deployed. After four orbit raises, the south panels were finally deployed, but with a 25% power loss and a 50% loss in satellite capacity.

Intelsat 19

The failure analysis committee eventually found that the problem was caused by a manufacturing defect in the sail panel. This defect caused permanent damage to the south sail panel of Intelsat-19 and prevented it from providing full power.