Issue 53

01 Flash Archive · Members Only

China Launches New SAR Satellites

China launched the SuperView Neo-2 01/02 SAR satellites on 16 July 2022, adding 50cm-resolution radar imagery capability to Siwei's planned commercial constellation.

Author Minhas Published July 31, 2022

16 Jul 2022: China launched two satellites onboard a Chang Zheng 2C from the Taiyuan Satellite Launch Center (TSLC). The payloads went to a Sun-Synchronous Orbit (SSO) and are called Siwei Gaojing-2 01/02, or SuperView Neo-2 01/02. The Synthetic Aperture Radar (SAR) satellites were constructed and operated by China Siwei Survey and Mapping Technology Co. Ltd. Launch Video.

– There was initial debate as to whether SuperView Neo-2 satellites are Electro Optical or SAR imagery. Neo-2 are believed to be SAR capable of producing 50cm resolution imagery when operating in spotlight mode.

– The Neo-2 satellites are in SSO as their NEO-1 predecessors which are confirmed high resolution electro optical satellites.

– Both satellite pairs are at similar altitudes and 97.4° inclination.

– The launch time of the NEO-2 satellites places them in a “dawn-dusk terminator” SSO which is more linked with radar/SAR satellites.

– Previously, Siwei launched 2x 30cm resolution SuperView 1 satellites on 29 Apr 2022.

– For their final constellation, Siwei is planning to launch at least 28 satellites which will be divided into three different kinds of satellite systems.

– 16 Neo-1 satellites provide 20-30cm resolution imagery; 8 Neo-2 satellites provide SAR images with a 50cm resolution.

– 4 Neo-3 satellites will collect “large swath-width, optical images” with 1m or better resolution. These have a worse resolution than the Neo-1 but can capture a bigger frame for their images. It is not known when the first Neo-3 will launch.

– The final constellation will provide information to a variety of providers in the civil and defense sector for civil mapping, agriculture management, energy and transportation infrastructure, disaster monitoring, and more.

Siwei Survey & Mapping Tech is technically a commercial company, but is a subsidiary of the China Aerospace Science and Technology Corporation (CASC), which is the main state-owned Chinese contractor for the construction of launch vehicles and rocket systems.

SuperView Neo-2 launch vehicle on transport.

Taiyuan Satellite Launch Center mission banner.

Long March 2C with SuperView Neo-2 payloads on the pad.

NEO-2(01/02) and NEO-1 orbit visualization.

02 Flash Archive · Members Only

Chinese Company Launches ZK-1A & 6 Satellites

CAS Space launched China's ZK-1A solid rocket with SATech-01 and five rideshare microsatellites on 26 July 2022.

Author Minhas Published July 31, 2022

26 Jul 2022: CAS Space launched the most powerful solid rocket built in China, the Zhongke-1A (ZK-1A), from their own newly built launch pad at the Jiuquan Satellite Launch Center. The main payload was SATech-01, while 5 piggyback microsats shared the ride. Launch Video & Cool Animation.

– CAS Space, also known as Zhongke Aerospace, is a spinoff company partially owned by the Chinese Academy of Sciences. The company developed the Zhongke-1A vehicle, also known as the ZK-1A or Lijian-1, based on the existing DF-31 road-mobile ICBM. This is one of several Chinese launch vehicles with solid-fueled ICBM heritage.

– The ZK-1A is reportedly capable of lifting 1,500 kg to a 500-km SSO, making it the most powerful solid launch vehicle in China, eclipsing the current Long March 11.

– CAS Space is also working on larger solid rockets and reusable liquid launchers.

– The main payload is SATech-01, also known as SY-01. SY-01 is a new space technology test satellite featuring the High Energy Burst Searcher (HEBS), designed to monitor gamma-ray bursts associated with gravitational wave events such as colliding black holes.

– The other spacecraft include the Huawan-Nanyue Kexue science satellite, the Chuangxin-15 satellite, 2 electromagnetism research satellites, and a GNSS atmospheric density measurement satellite. One of the microsatellites reportedly had a quantum key on board, as part of China’s work on developing quantum communications.

– CAS Space is planning to fly a medium-lift rocket known as the ZK-2 with a core similar to the ZK-1A plus two solid rocket boosters with the same width as the core. The first flight could occur at the end of 2022.

– A ZK-3 small liquid launcher with greater capability to SSO is also being developed. CAS Space is also developing the vertical takeoff/vertical landing ZK-4, ZK-4A, and ZK-5 rockets with liquid-fueled engines and the ZK-6 suborbital space tourist rocket.

China’s state-owned and commercial space entities have been developing a range of solid rockets with varying capabilities in recent years, with the trend seen as an effort to boost the country’s overall space capabilities.

ZK-1A payload lineup including SATech-01 and five rideshare microsatellites.

CAS Space launcher concepts: ZK-3, ZK-4, ZK-4A, ZK-5 and ZK-6.

ZK-1A inaugural orbital launch.

03 Flash Archive · Members Only

China: Jilin Imagery Constellation Sending Data “Pips”

Amateur astronomer Scott Tilley observed unusual L-band data "pips" from 29 Jilin imaging satellites, with no publicly identified purpose.

Author Minhas Published July 31, 2022

26 Jul 2022: Amateur Astronomer Scott Tilley noted strange wideband data “pips” emanating from the Jilin imagery constellation. With respect to these L-band signals, Jilin is acting like a mobile-satellite communications system. See Video.

– Mr Tilley observed a total of 29 JILIN spacecraft emitting ‘pip’ emissions between 1613.8-1626.5MHz.

– The ‘pips’ appear to be about +3MHz in bandwidth and ~0.5 seconds in duration.

– The transmission interval is around 4-10 seconds when they are active but many spacecraft are not active on each pass and when they are they may not ‘pip’ for the entire pass and may even change their ‘pipping’ rate.

– The pipping appears to be most pronounced during the daytime. They are active at night but much less so than during daylight.

– Mr Tilley found no reference on ITU filings or in news reports about why there would be data ‘pips’ coming from the JILIN satellites. He notes the only other service that remotely matches the Mobile-satellite service from China that is presently active is the GEO based TIANTONG system which uses different frequencies.

– The diurnal behavior of the system could mean that it is either driven by human activity or it could be part of the primary JILIN optical Earth imagery mission, perhaps allowing a client to place a transponder on an asset and have the spacecraft interrogate it and image its location as it moves around. It is possible this could be some sort of asset tracking system.

The JILIN system is operated by Chang Guang Satellite Technology Company in Beijing. No public references have been found about what the purpose of these emissions from the satellites is.

Jilin constellation day "pipping" activity.

Jilin constellation night "pipping" activity.

JILIN-01 GAOFEN 3D Doppler analysis.

Example of a JILIN data-pip sequence.

04 Flash Archive · Members Only

China Paper: Shi Jian (SJ) and Shi Yan (SY) Projects

A CASI paper reviews how China's Shi Jian series established operational practices while Shi Yan satellites served earlier technology-piloting roles.

Author Minhas Published July 31, 2022

28 Mar 2022: The Chinese Aerospace Studies Institute, part of the USAF Air University, published a short paper describing the history of Chinese experimental SJ and SY satellites up to 2013. Read the paper.

– “Shi Jian” indeed means “practice” but as a noun, such as “best practice”, or as in “put into practice.”

– Chinese linguists argue against translating “Shi Yan” as “experiment,” so “pilot” or “trial” are more applicable.

– Both the SJ and SY series have for decades contributed to what Beijing now refers to as the China High-resolution Earth Observation System (CHEOS).

– SJ satellites have primarily improved methods for radar and infrared payloads and SY vehicles have primarily enabled testing of other optical payloads.

– The SJ series has 30 more years of history and a corresponding larger variety in missions and payloads. It has also regularly played a role in establishing best practices for data transmission and communications, and on-orbit satellite constellation guidance and control.

– In 2013, after being jointly launched, the SJ-15 and Shi Yan-7 conducted their only publicly known rendezvous and proximity operation (RPO), which seemed to be coordinated.

– Information on these early launches illustrates that China’s focus for the SJ series was on establishing best practices and operational procedures to enable the development of China’s space program.

– To begin professionalizing Chinese space operators, engineers used lessons learned from the first four SJ satellites to publish Mandarin space operations manuals such as the Handbook of the Artificial Satellite Environment and Handbook on Low Earth Orbit Space Environment.

– The SJ series improved methods for satellite control after launch, a general requirement especially necessary for enhanced imagery with two satellites flying in formation.

– The first Shi Yan was initiated and designed by the Harbin Institute of Technology and launched in 2004, nearly 30 years after the start of China’s space program.

– Shi Yan-1 was China’s first stereoscopic imaging satellite for terrain mapping, and the first ten years of the series saw Shi Yan 1-5 focused on piloting as many payloads as possible, probably optical sensors, on one satellite close to 200 kg.

China has historically used the SJ series to establish operational best practices and procedures for systems or techniques already adopted. The SY satellites appear to play an earlier role in the space systems development process, piloting multiple new technologies on one satellite bus to develop an efficient payload-integration platform and determine payload applicability.

Shi Jian - usage: best practice or procedure.

Shi Yan - usage: pilot or trial.

05 Flash Archive · Members Only

This Fortnight in GEO

This Fortnight in GEO tracks TJS-3, Tianlian-2(03), Luch/Olymp and SJ-17 maneuvers across the geostationary belt.

Author Minhas Published July 31, 2022

– TJS-3 reversed course and is now drifting eastward towards its original position in early-July.

– Tianlian-2 (03) relay satellite circularized its orbit and is now at 10°E.

– Russian Luch/Olymp Satellite initiated 2° per day westward drift, now 2,900kms from previous station.

– SJ-17 reduced altitude and initiated .48° per day westward drift. Briefly in vicinity of Fengyun-2F.

Forget Something? TJS-3 Reverses Course: In early July TJS-3 was at 59°E when it increased its altitude and began a westward drift. TJS-3 proceeded to 51.2°E, ~900km from its original position earlier in the month.

– On 22 July TJS-3 decreased its orbit ~100km and reversed its drift. It is now back to 57.5°E and continuing to drift east <1°/day.

– Soon after its launch in Dec 2018 TJS-3 conducted a series of maneuvers with the TJS-3 AKM. Watch Video.

– Chinese news media reported TJS-3 will test “double satellites co-position communications” as well as “multi-frequency and high speed comms”.

Tianlian-2(03) Update: As anticipated the new Chinese data relay satellite, Tianlian-2(03), circularized its orbit and has settled into China’s 10°E GEO slot.

– China recently relocated TL-1 (05) closer to TL-1 (03) leaving the 10°E slot vacant. Tianlian-2(03) is the most inclined of China’s 2d generation relay satellites. TL-2(03) is 3° inclined, TL-2(02) is 2.4° and TL-2(01) is only .1° inclined.

– China has 7 current data relay satellites. Four are first generation TL-1 satellites and three are second generation TL-2. China’s first TL-1 is in a supersynchronous orbit and no longer active.

Russian Luch/Olymp Initiates Westward Drift: Prior to 21 Jul 2022 Luch/Olymp maneuvered to decrease its orbit ~140km resulting in a 2° per day westward drift. It drifted from 61.8°E to 35.8°E (~2,900km).

– Over the past 2 weeks Luch/Olymp has been in the vicinity of SKYNET 5D and PAKSAT 1R. Prior to the maneuver Luch/Olymp had been in vicinity of Intelsat-33 since October 2021.

– During its eight years on orbit, Luch has parked near more than two dozen commercial communications satellites for periods ranging from a few weeks to nine months and typically close enough to be within the typical ground terminal uplink window.

Hello Old Friend: SJ-17 Maneuvers: SJ-17 decreased its altitude ~34 km and is now drifting west at ~.48° per day. It relocated from 117.5°E to 111.31°E and continues to drift westward.

– SJ-17 was periodically in the vicinity of Fengyun 2F, a Chinese weather satellite, early on 29 July.

SHIJIAN-17 is an experimental satellite that carries an electric thruster test package, a type of propulsion system that could give the spacecraft great maneuverability to efficiently adjust its orbit and move around the geostationary belt. General James Dickinson, then Commander of U.S. Space Command, stated in Congressional testimony that the SJ-17 also carried a robotic arm that could be used for dual use capabilities.

Editor’s Note: Orbital information is courtesy of the 2022-07-22 and 2022-07-29 Space Domain Awareness Reports from Palski & Associates Inc.

TJS-3 maneuvers during July 2022.

TJS-3 altitude and longitude maneuver graphs.

Second-generation TianLian relay constellation.

Luch/Olymp heads west by approximately 2,900 km.

Luch/Olymp longitude and drift history.

SJ-17 mission profile - longitude history.

SJ-17 and Fengyun-2F proximity view, 29 July 2022.

Satellite-location overview as of 29 July 2022.

07 Flash Archive · Members Only

China Adds Wentien Module to Space Station

China launched the 23-ton Wentian laboratory module to its space station on 24 July 2022 aboard a Long March 5B.

Author Minhas Published July 31, 2022

24 Jul 2022: China launched the Wentian experiment module on a Long March 5B rocket from the Wenchang spaceport on the southern Chinese island of Hainan, with crowds watching on from nearby public beach areas. The LM-5B first stage was expected to re-enter Earth’s atmosphere on 31 July. Watch Launch. Watch Video Describing Wentien.

– Wentian (“Quest for the Heavens”) is a laboratory cabin module (LCM), and one of the three major modules of the Chinese Space Station. It will not only provide science space for the station, but also additional navigation capabilities, avionics, propulsion, and orientation control.

– The Wentian module had a mass at takeoff of 23,000 kilograms and is designed to host a range of science cabinets for on-orbit experiments.

– Wentien also provides backup life support and propulsion for Tianhe, which launched in Apr 2021.

– The country has now successfully launched eight space station-related missions for the project, including two modules, three cargo spacecraft and three crewed missions. A third module, named Mengtian, is expected to launch in Oct.

– While the launch and docking were successful, the large first stage of the Long March 5B rocket, which entered orbit along with Wentian, was expected to re-enter Earth’s atmosphere on 31 Jul.

The re-entry would be uncontrolled and location of the debris field unknown. The previous LM-5B left debris that fell into the Indian Ocean (no damage was reported).

Wentian laboratory module launch on Long March 5B.

Wentian module interior.

Wentian module interior after docking.

08 Flash Archive · Members Only

Jack’s Astro Corner: Right Ascension of the Ascending Node (RAAN) – Let’s Do the Twist (Part IV)

Jack's Astro Corner explains RAAN as the 'twist' of the orbit, introduces GEO polar plots, and demonstrates why inclination and RAAN must both be matched.

Author Minhas Published July 31, 2022

Over the summer, Jack Anthony will break down each of the six orbital elements required to uniquely identify a specific orbit and satellite in that orbit. This week we examine Right Ascension of the Ascending Node (RAAN). For those who can’t wait the entire summer, please visit Jack’s “Orbit Element Dance” on YouTube, featuring Jack demonstrating this way to learn the six classical orbital elements (COE). Orbit Element Dance.

Jack uses the STP method of remembering the 6 COEs: Size, Shape, Tilt, Twist, Position of Perigee and Position of the Satellite at a particular time. The second “T”, the Twist of the orbit, is Right Ascension of the Ascending Node (RAAN).

The Ascending Node is where the satellite passes through the equatorial plane as it ascends from the south hemisphere to the north. The principal axis of the Earth-Centered Inertial (ECI) coordinate frame is the I or X axis, and that is the reference used to determine RAAN.

The I-axis points toward the Vernal Equinox. It points to a direction fixed relative to the stars rather than a geographic point on Earth. Earth’s axis precession shifts this reference slowly over the centuries.

The other vector needed to determine RAAN is the Node Vector in ECI pointing to the Ascending Node of the orbit. The angle between the I-axis and the Node Vector is RAAN, denoted Ω (large Omega).

RAAN can have values from 0 to 359 degrees. It is the twist or swivel of the orbit plane and is measured eastward from the I-axis using the Right-Hand Rule.

RAAN is relative to the ECI frame. It is not tied to the longitude of the Earth; it is an inertial reference, not a geographic reference.

The article then introduces the Polar Plot used by GEO satellite operators and orbit planners. It combines inclination and RAAN in one display. Inclination and RAAN are both required to define the orbit plane.

Jack’s Polar Plot places inclination on concentric circles, with zero inclination in the center, while RAAN is shown around the plot beginning at the 3 o’clock position and increasing counter-clockwise through 360 degrees.

A worked example uses a GEO refueling satellite, the “Guardian Gas-n-Go,” that must rendezvous and dock with a client satellite. The client is in an orbit with inclination 4 degrees and RAAN 90 degrees, while the refueler begins at inclination 3 degrees and RAAN 135 degrees.

The most fuel-efficient plane match uses one combined burn that increases inclination by 1 degree and rotates RAAN by 45 degrees. The article’s spreadsheet example gives a required Delta-V of 152 m/sec.

If the operator changes only inclination, the article gives 54 m/sec for the first burn but notes the RAAN remains unmatched. A second 164 m/sec burn would then be required to twist the orbit plane, totaling 218 m/sec – 66 m/sec more than the single combined maneuver.

The bottom line is that the orbit plane is defined by Inclination and RAAN. Matching only inclination is inadequate for an orbit-plane match before rendezvous and refueling.

A GPS example shows why: GPS satellites have inclinations of about 55 degrees but occupy many different orbit planes because they have different RAANs.

Finally, the Polar Plot is used to visualize the roughly 54-year inclination/RAAN cycle of uncontrolled GEO satellites. The article describes the resulting “Conga Line” of spacecraft progressing around the plot.

In conclusion, RAAN is the angle between the I-axis of the ECI frame and the Ascending Node vector of the satellite’s orbit. The Polar Plot is a tool for keeping track of the orbit plane. Next time: Argument of Perigee.

STP method for remembering the six classical orbital elements.

ECI coordinate frame and Vernal Equinox reference direction.

RAAN geometry showing the line of nodes and orbit plane.

Jack's Polar Plot for inclination and RAAN.

Polar Plot showing client and refueler orbit planes.

Polar Plot illustrating the refueler orbit plane.

GPS satellites in multiple orbit planes produced by differing RAAN values.

GEO inclination/RAAN 54-year cycle - the 'Conga Line'.

09 Flash Archive · Members Only

Pics o’ the week!

Pics o' the week includes an early Air Force tracking center, JoAnn Morgan at Apollo 11, the new KZ-1A booster poster, Jupiter's north pole, NASA Dragonfly, Sohae launch-site modernization and a launch-plume image.

Author Minhas Published July 31, 2022

US Air Force space tracking center (early 1960s)

JoAnn Morgan was the only woman working in the launch firing room for Apollo 11, which landed on the Moon 20 July 1969. It would be one of many ceilings Morgan would break during her 45 years at NASA.

“Movie Poster” of New KZ-1A Booster

Jupiter’s North Pole imaged by NASA Juno on 5 July 2022

Dragonfly: So this…this is COOL. We’re sending an octo-copter to one of Saturn’s moons, Titan. Titan has an atmosphere about 4x denser than Earth.

Not nearly as cool… North Korea begins first stages of construction to modernize the Sohae Satellite Launching Station.