Small Is Beautiful: US Military Explores Use of Microsatellites
At a time when defense budgets are being cut, the era of the multi-billion dollar military satellite program might be over. Witness the fate of the massive $12 billion TSAT program, which was shut down in 2009. As a much cheaper alternative, governments are exploring the possibility of using microsatellites to perform many of the functions currently performed by expensive large satellite systems: GPS navigation, communication, surveillance, and earth imagery.
At a 10th of the cost of their larger cousins, microsatellites are much easier sell to budget conscious procurement officers. They are much cheaper and faster to build and launch. For key military missions, however, their reliability and longevity are an issue. They might be cheaper, but if the military has to use 10 times as many to do the job of traditional satellites, would that be a cost savings?
This DID Spotlight article will focus on the US military’s microsatellite development and launch programs, as well as the Army’s development of nanosatellites for battlefield communication, and take a brief look at the problem of space debris.
Microsatellites: Definitions and Technologies
Before we dive into a discussion of microsatellite technologies and programs, let us define what a microsatellite is. According to the Small Satellites Home Page, microsatellites are satellites between 10 and 100 kilograms (22-220 pounds). They are one category of small satellites. Other categories, from largest to smallest, are minisatellites, 100-500 kilograms (220-1100 pounds); nanosatellites, 1-10 kilograms (2.2-22 pounds); picosatellites, 0.1-1 kilogram (0.22-2.2 pounds); and femtosatellites, less than 100 grams (0.22 pounds).
Microsatellite projects typically involve rapid developmental timetables for experimental missions, with initiation to launch schedules in months to a few years. Often, commercial-of-the-shelf (COTS) technology is used and modified for microsatellite projects, even for military systems. Using COTS technology helps with the plug-and-play approach to microsatellite construction. By having pre-made, interchangeable components, microsatellites can be assembled to order and launched in a relative short time, sort of like Legos.
DARPA, the Pentagon’s R&D arm, has been working on a number of microsatellite technologies designed to reduce their weight and improve reliability and performance. These technologies include lightweight optical space surveillance/situational awareness sensors; lightweight power, chemical and electric propulsion systems; advanced lightweight structures; advanced miniature RF technology, including micro crosslink and use of COTS approaches; active RF sensor technology; COTS processor and software environment; miniature navigation technologies, including the use of starfields for deep space navigation; and autonomous operations technology.
Microsatellites are cheaper to make and launch. Smaller launch vehicles can be used to launch multiple microsatellites into orbit, or microsatellites can piggyback on rockets blasting larger payloads into space.
In addition to being faster and cheaper, microsatellites can be used for missions that larger satellites can’t perform, such as setting up a constellation of communication nodes or conducting in-orbit inspection of larger satellites. They could even be used as anti-satellite weapons to destroy key satellites of opponents. Some observers have judged that the BX-1 microsatellite deployed by China in 2008 was an experimental anti-satellite weapon.
The slogan for the small satellite approach is “faster, better, smaller, cheaper” – a slogan that the Pentagon has embraced with gusto.
Pentagon’s TacSat Program
The Tactical Satellite (TacSat) microsatellite program grew out of the work of the Pentagon’s Office of Force Transformation to develop an operationally responsive space (ORS) capability that would deliver satellites on relatively short notice (compared to traditional satellites) to meet the urgent C4ISR needs of battlefield commanders.
In its 2007 report to Congress [PDF], the Pentagon said that the ORS effort had three goals: “first, to rapidly exploit and infuse space technological or operational innovations; second, to rapidly adapt or augment existing space capabilities when needed to expand operational capability; and third, to rapidly reconstitute or replenish critical space capabilities to preserve operational capability.”
These goals drove the ORS concept “to improve the responsiveness of existing space capabilities (e.g., space segment, launch segment, ground segment) and to develop complementary, more affordable, small satellite/launch vehicle combinations and associated ground systems that can be deployed in operationally relevant timeframes.”
To oversee this effort, DoD set up the ORS Office in 2007 at Kirtland Air Force Base, NM. The office was tasked to integrate the ORS program; one of its focuses has been development and deployment of TacSat microsatellites. The TacSat program, which includes 8 TacSat, involves participation from the Naval Research Lab (NRL), the Air Force Research Lab (AFRL), the Army’s Space and Missile Defense Command, and the Air Force Space Command, as well as the ORS Office.
During 2003 and 2004, TacSat-1 was developed, produced, and tested for less than $10 million. The satellite was a 220 pound-class microsatellite with electronic intelligence capabilities, including specific emitter identification (SEI), visible and infrared imaging, and cross-platform capabilities. Both the SEI and cross-platform mission payload used a low-cost receiver (LCR-100) design.
The TacSat-1 bus, based on Orbital Sciences’ Orbcomm FM29 satellite, was designed to carry three payloads into low earth orbit: an infraSPOT Indigo Omega infrared camera, a HanVision HVDUO-F7 visible camera, and a Copperfield-2 payload capable of detecting, tracking, and identifying pulsed radio frequency signals. The satellite had the capability to task and disseminate data through the Pentagon’s secret SIPRNET network.
However, the launch of TacSat-1 aboard the SpaceX Falcon rocket, set for March 2006, was postponed because of problems with the Falcon. After a number of launch delays, the Pentagon decided to cancel the TacSat-14s launch in 2007 because TacSat-2 had already been successfully launched.
TacSat-2 and Beyond
For TacSat-2, the ARFL joined with the NRL to build on the TacSat-1 bird. The objectives of the TacSat-2 Roadrunner satellite were to test the requirements for and limitations of rapid development and deployment of spacecraft and payload, as well as concepts of operations (CONOPs) for microsatellites.
TacSat-2 was an imaging and RF satellite that provided tactical CDL and UHF links and used a Fairchild Imaging CCD 583 Time Delay Integration (TDI) Line Scan array. The TDI process enabled the satellite to scan the earth at high speeds and provide a high resolution image to ground commanders. Unlike TacSat-1, TacSat-2 was successfully launched Dec 16/06 aboard an Orbital Sciences’ Minotaur 1 rocket from the Mid-Atlantic Regional Spaceport at the southern tip of NASA’s Wallops Flight Facility, VA.
For TacSat-3, partners included ONR, AFL, and the Army Space and Missile Defense Command; ATK was the satellite manufacturer. TacSat-3 is an imaging satellite that consists of three payloads: the ARTEMIS hyper spectral imager (HSI), the Ocean Data Telemetry Microsatellite Link (ODTML), and the Space Avionics Experiment (SAE).
The primary payload, the ARTEMIS HSI, developed by Raytheon, supplies target detection and identification data, as well as initial preparation of the battlefield and battle damage assessment information. The ODTML collects data from sea-based buoys and transmits it to ground stations. Demonstrating a plug-and-play capability, the SAE integrates payload and spacecraft bus employing reprogrammable components.
TacSat-3 was launched on May 19, 2009, aboard a Minotaur-1 rocket from the Mid-Atlantic Regional Spaceport and became operational in May 2010 after completing testing and a mission demonstration in the field.
TacSat-4 is a communications satellite that provides 10 UHF channels that can be used for communication, data collection and transmission, and/or Blue Force Tracking. The project is led by the NRL with participation from the Pentagon, the Air Force, Army, Marines, and US Strategic Command. TacSat-4 provides communications-on-the-move capabilities for existing radios without requiring antenna pointing and provides a wideband MUOS-like channel for early testing.
TacSat-4 has a 1000W solar array and a 12-foot diameter payload antenna. The satellite will operate in low HEO (highly elliptical orbit) with 6 orbits per day that provides long dwell time over theater. The low HEO orbit augments existing communications satellites in geostationary orbit. Construction of TacSat 4 was completed at the end of 2009, but its scheduled launch aboard a Minotaur IV rocket was delayed and is now set for spring 2011.
TacSat-5 is being led by AFRL and will test plug-and-play technology for all internal and external bus interfaces. This is intended to enable the rapid assembly of microsatellites to meet commanders’ urgent needs. In October 2009, 11 contracts were let for development of TacSat-5. TacSat-6 is expected to be a communications satellite; TacSat-7 and TacSat-8 are still in the mission planning stage.
A spinoff of the TacSat program is the ORS-1 microsatellite, which is designed to provide continuous battlefield ISR. The ORS-1 satellite, built by ATK, grew out of the success of TacSat-3. ATK used the TacSat-3 bus to build the ORS-1 satellite with the addition of a propulsion module.
In June 2010, the Pentagon requested reprogramming of $3.9 billion in appropriations for the ORS program; $15.7 million of that was redirected to fund the launch of the ORS-1 microsatellite . ORS-1 was successfully launched aboard a Minotaur-1 rocket from the Mid-Atlantic Regional Spaceport in Wallops Island, VA at 11:09 p.m. EDT on June 29/11.
One MiDSTEP for DARPA
Under its Microsatellite Demonstration Science and Technology Experiment Program (MiDSTEP), DARPA is developing advanced technologies and capabilities to demonstrate a suite of lightweight technologies integrated into high-performance microsatellites.
One of the MidSTEP’s projects is the Microsatellite Technology Experiment (MiTEX). MiTEX is actually 2 microsatellites, one built by Lockheed Martin and the other by Orbital Sciences. The NRL built the upper stage kick motor for both satellites.
The satellites were successfully launched into geostationary orbit on June 21/06 aboard a Delta II rocket from Cape Canaveral Air Force Station (AFS). Over the next few years, they conducted experiments in autonomous operations and maneuvering and station-keeping. Both MITEx satellites maneuvered close to the defunct DSP early warning satellite. The first made a flyby on Dec 23/08 and the second on Jan 1/09.
DARPA has been reticent about what specific capabilities MiTEX was supposed to demonstrate. In its budget justification for the project, the agency said:
“The Microsatellite Technology Experiment (MiTEx) technology demonstration investigated and demonstrated advanced high-payoff technologies from a variety of potential candidates, including: lightweight power and propulsion systems, avionics, structures, commercial off-the shelf (COTS) components, advanced communications, and on-orbit software environments. MiTEX flight tested a new, experimental upper stage, and demonstrated small COTS technologies to support a fast-paced, low-cost, lab-like, build-to-launch satellite approach in a shared industry/government environment.”
Not very specific. At least one pundit wonders if the MiTEX microsatellites were designed to demonstrate anti-satellite warfare capabilities.
Another DARPA innovate microsatellite program is Systems F6 (Future, Fast, Flexible, Fractionated, Free-Flying Spacecraft), which aims at removing the constraints of traditional satellite programs. The F6 program rides on a number of trends, including the rapidly changing face of computing, and a steady rise in mini- and microsatellites.
System F6 will divide up the tasks performed by a large satellite (power, receivers, control modules, etc.) and assign each task to a dedicated micro-satellite. By communicating with each other in a cluster, the idea is that the cluster would provide the same overall capability as a traditional satellite.
By allowing the various functions of a spacecraft to be developed and launched separately, this type of “fractionated” system reduces overall program risk, provides budgetary and planning flexibility, speeds initial deployment, offers greater survivability – and allows future technologies to build on existing efforts, in order to create something totally new.
The program requires development of open interface standards to enable the emergence of a space “global commons.” A program goal is the industry-wide promulgation of these open interface standards for the sustainment and development of future fractionated systems.
Army Nanosatellites: Smaller Is Better
While the Navy and Air Force have been focused on the potential of microsatellites, the US Army’s view is that smaller is better. The Army’s Space and Missile Defense Command/Army Forces Strategic Command (USASMDC/ARSTRAT) has launched a program to develop communication nanosatellites.
Nanosatellites are designed to serve as nodes for battlefield communication. The Space and Missile Defense Command: Operational Nanosatellite Effect (SMDC-ONE) program plans to develop many of these satellites and place them into low earth orbit to provide as-needed tactical communications capability. The satellites will be able to send and receive data files from a ground command and relay the data to other ground stations.
The Army ordered eight SMDC-ONE nanosatellites from Ducommun’s Miltec Corp., which were delivered in April 2009. Each satellite weighs less than 10 pounds, is 4x4x13 inches in size, and costs less than $1 million to produce. Production of all 8 satellites took less than a year.
The USASMDC/ARSTRAT describes the overall purpose of the SMDC-ONE nanosatellite program [PDF] as follows:
“Nanosats deployed in large numbers can provide enhanced capabilities over large latitudinal swaths of the earth or even globally. Because they are low cost, they can be ‘refreshed’ frequently by launching replacements, which allows rapid technology upgrades, reduces the unit reliability requirements, and allows for manufacturing economies of scale. A nanosat constellation populated by inexpensive spacecraft could be useful in tactical ground operations, humanitarian support, and stability operations. If some satellites are lost, they can be rapidly reconstituted. They can provide coverage over specific regions as well as globally.”
The Army successfully blasted its first nanosatellite into orbit on Dec 8/10 from Cape Canaveral. This was the first launch of an Army-built satellite in more than 50 years. The satellite launched onboard a Falcon 9 two-stage booster as a secondary payload. The satellite was able to communication with the ground station and remained in orbit for 30 days.
For future missions, the Army is considering developing nanosatellites with on-board GPS capability, S-band communications link for increased data transmission, inclusion of a software defined radio for greater transceiver frequency flexibility, and modification of the radios to increase the available volume for payloads.
Tracking Space Debris
Orbital or space debris has become a growing concern to the worldwide space community. Space debris is the collection of junk orbiting the earth that is left over from all the human space activity that has taken place since Sputnik was first blasted into orbit. This debris can damage spacecraft and injure or even kill astronauts. It is a particular concern for microsatellites and nanosatellites because of their small size and light weight, which reduce the protection that can be incorporated into them.
The Air Force is working on a couple of projects to track orbital debris. One is called the Space Fence, a project to deploy ground-based S-band radars. The $3.5 billion program is replacing the Air Force’s VHF radar fence that currently tracks orbital space objects. The existing system is called a fence because several transmitter and receivers create a narrow, continent-wide planar energy field in space. The higher wave frequency of the new system will enable better detection and monitoring of microsatellites and space debris.
The first phase of the Space Fence development has been completed. During the 2nd preliminary design phase, the Air Force is awarding 2 contracts worth up to $214 million to 2 of the 3 companies that participated in phase 1: Lockheed Martin, Northrop Grumman, and Raytheon.
The Space Fence program “will allow us to reduce susceptibility to collision or attack, improve the space catalog accuracy and provide safety of flight,” said Linda Haines, Space Fence program manager at the Air Force’s Electronic Systems Center.
The Air Force is also building a satellite constellation to track orbital objects from space, called the Space-based Space Surveillance (SBSS) program. The satellites will detect and track space objects, such as microsatellites and debris.
On Sept 25/10, the Air Force successfully launched the 1st SBSS satellite, Block 10, from Vandenberg Air Force Base, CA, aboard a Minotaur IV rocket. Block 20 will provide more robust capability and will be composed of a constellation of 4 satellites.
Future: Faster, Better, Smaller, Cheaper
The future of microsatellites can be summed up by the slogan with which we began this discussion – “faster, better, smaller, cheaper.” The US military will continue to work on improving each aspect: getting microsatellites into space faster, improving their performance and durability, making components even smaller, and, above else, making them cheaper to build and deploy.
One area for future research is the miniaturization of propulsion systems. Propulsion systems for early satellites were bulky and expensive. However, with advances in micro-electromechanical system |PDF] (MEMS) and pulsed plasma thruster technology, small satellites should soon be able to perform just like their larger cousins.
The future of microsatellites might look more like DARPA’s System F6, in which constellations of microsatellite components form a network that can perform the tasks of a large satellite. Of course, such a future requires the development of open interface standards to enable the emergence of a such a constellation.
However, open interface standards are by definition known to the public. So as military microsatellites progress, the issue of information security is likely to become front and center.
At the same time, the attractiveness of small satellites produced cheaply and launched quickly cannot be denied. In the area of satellites, small is beautiful.
Key Contacts as of February 2011
- Joseph P. Bellino, Ducommun, Vice President and Chief Financial Officer, phone: 310-513-7211; jbellino at ducommun.com
- Tom Gathmann, Boeing, Space Based Space Surveillance Program, phone: 562-797-4239; email: thomas.p.gathmann at boeing.com
- RayMing Chang, US Air Force, Space and Missiles Systems Center, email: rayming.chang at losangeles.af.mil
- Michael Hurley, Naval Research Lab, Spacecraft Engineering Department, phone: 202-767-0528; email: mhurley at space.nrl.navy.mil
- Bob McCoy, Office of Naval Research, Tactical Satellite Program, phone: 703-696-8600; email: bob.mccoy at navy.mil
- Peter Wegner, Operationally Responsive Space Office, Director, phone: 505-853-3486; email peter.wegner at kirtland.af.mil
- Small Satellites Home Page – Satellite classification
- Office of Naval Research – Tactical Microsatellite (TacSat)
- GlobalSecurity.org – TacSat / Joint Warfighting Space (JWS)
- Ducommun/Miltec – US Army Space and Missile Defense Command/Operational Nanosatellite Effect [PDF]
- Boeing – Space Based Space Surveillance System
- US Army (Dec 8/10) – Army nanosatellite on first flight
- Space News (Aug 30/10) – Rapidly Delivered Systems
- USAF (June 10/10) – Tactical Satellite-3 completes groundbreaking experimental mission
- DARPA (February 2010) – FY 2010 President’s Budget Request: MiDSTEP Program [PDF]
- Aviation Week (Jan 7/10) – Darpa Pursues On-Orbit Networking
- The Space Review (Oct 20/08) – China’s BX-1 microsatellite: a litmus test for space weaponization
- Air Force Magazine (September 2009) – Game Changers [PDF]
- BBC (July 19/07) – Microsatellites ‘pose global threat’
- DoD (April 20/07) – Report to Congress: Plan for Operationally Responsive Space
- The Space Review (July 31/06) – Mysterious microsatellites in GEO: Is MiTEx a possible anti-satellite capability demonstration?