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Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
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5
Small Launch Vehicles

The effective use of small satellites to fulfill Earth observation needs depends on the availability and costs of launch vehicles. As spacecraft become smaller and less expensive, so also must launch vehicles, or launch costs will become disproportionately large. Additionally, the trend toward smaller spacecraft implies a commensurate increase in the number and rate of launches. It is well known that long launch queues, slips, and delays can increase overall mission costs. Similar problems with small missions are likely to have even greater impacts due to limits on launch site capacity.

Selecting the appropriate launch vehicle for a particular mission involves mission architecture trade-offs reflecting the number of satellites to be launched, orbit requirements, satellite on-board propulsion, and launch vehicle performance. Missions that call for multiple satellites in common orbit planes can accrue cost benefits with multisatellite launches on higher performing launch vehicles. Satellites that must carry on-board propulsion for orbit maintenance or attitude control can sometimes effectively exploit lower performance, lower cost launch vehicles to place them into low initial orbits and then use their own propulsion systems for final orbit insertion. Whatever the specifics, the launch vehicle must be matched to the mission if costs are to be minimized. Excess launch capacity beyond prudent margins represents wasted costs.

Recognizing that the move toward smaller spacecraft places added emphasis on the costs and availability of appropriate launchers, the aerospace industry has moved to develop a number of "small" launch vehicles tailored specifically to meet this growing market segment. This chapter presents an overview of these small launchers in terms of their known costs, performance parameters, capabilities, and performance records.

U.S. launchers were emphasized in this assessment, since current U.S. policy precludes the launching of government-funded spacecraft on foreign launch vehicles. Launchers based on converted ballistic missiles were also excluded on the grounds of current U.S. policy. Formal policy states that the use of converted ballistic missiles is restricted to government payloads only, and then only when such use would result in significant savings over the use of commercial launch services. Statements by administration personnel indicate that any requests to use a converted ICBM (Intercontinental Ballistic Missile) for an orbital flight would meet with strict scrutiny. In general, the National Space Transportation Policy directs U.S. departments and agencies to purchase commercial launch services to the fullest extent feasible. In the event that U.S. policy changes, some discussion of foreign launch vehicles is provided for a more complete assessment of small satellite launch capabilities.1

1  

 The situation with launchers is changing rapidly. The military, among others, is petitioning to allow use of foreign launchers; at the

Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×

SMALL LAUNCH VEHICLES FOR EOS AND NPOESS

This section covers launch vehicles capable of launching to the Earth Observing System (EOS) and National Polar-orbiting Operational Environmental Satellite System orbits with mass performance capabilities up to and including the Delta II. While the Delta II may be considered excessive for the launch of individual 500 kg payloads (the upper limit of what this report defines as a small satellite), its capacity for launching multiple small spacecraft on a single launch vehicle merits its inclusion. Also, Boeing Corporation (which recently acquired McDonnell Douglas Co.) is developing a downsized version of the Delta II (Delta II-7320) to extend the utility of this reliable launch vehicle. However, this will still be a fairly high-performance launch vehicle with a relatively high absolute cost compared with the alternatives, suitable primarily for medium-sized or multiple small satellites. Within these guidelines, the launch vehicles considered here are the Delta II, Pegasus, Taurus, Athena (previously known as the Lockheed-Martin Launch Vehicle), and Conestoga. Further detail on these launch vehicles is provided in Appendix C, which also addresses the Eagle family of launch vehicles—the Eclipse Express and Astroliner, the PacAstro, and the Kistler booster. These launch vehicles, while all still in development, are included because of their potential for significant cost savings and market impact.

Pertinent data for the U.S. launch vehicles evaluated are presented in Tables 5.1 and 5.2. Table 5.1 summarizes their mass performance to a 700 km polar Sun-synchronous orbit, approximate cost, and performance history; Table 5.2 provides data on their fairing dimensions and launch environments. Table 5.1 also provides data for relevant foreign launch vehicles.

Generally, mission planners look to minimize mission costs. Because absolute launch vehicle costs increase with launch vehicle size and performance, the lowest performance (and hence lowest cost) launch vehicle that accomplishes the mission should be used. Preferably, the mission designer would have a series of launch vehicle options with increments in performance filling the gap between the low-capacity Pegasus and the high-capacity Delta II. Small launch vehicles such as the Pegasus and Athena 1 have limited capacity to put payloads into EOS orbit. However, these launch vehicles can be used for Earth observation missions by supplementing them with spacecraft on-board propulsion to enable them to reach the desired orbit (e.g., the Total Ozone Mapping Spectrometer Earth Probe). This approach is being used, but it results in some increase in spacecraft cost. The development of intermediate-capacity launch vehicles, such as the Taurus XL and Athena 2, helps fill this gap and offers more opportunity to optimize missions.

Fairing size is sometimes another criteria in selecting a suitable launch vehicle for a mission in that it must accommodate the stowed payload. It is preferable that launch vehicle candidacy not be limited by fairing size but by performance to orbit. Thus, most manufacturers are developing larger fairings for their vehicles for added utility. The fairing size for the Pegasus, however, which does impose significant size constraints, is limited by its airplane launcher system.

Figure 5.1 plots the cost and performance data for operational and planned U.S. launch vehicles as the specific cost per unit payload (satellite) mass to the EOS orbit versus launch capacity. For operational launchers, the minimal cost per unit mass to orbit is achieved with the Delta II and increases with decreasing or increasing launch vehicle capacity. The cost per pound penalty is severe for small launchers with payloads under 500 kg. It is this superior cost efficiency of the Delta II, along with its excellent reliability, which makes launching multiple satellites on a single Delta II an attractive alternative to multiple smaller launch vehicles when possible. In fact, early experiences (failures) with new, smaller launch vehicles indicate that reliability is a major concern, as indicated by the success rates shown in Table 5.1. It will probably take several years and more failures before any small launch vehicle achieves the reliability of the Delta II (>95 percent).

   

same time, a major issue is cooperation with and technology transfer to China. Complicating this issue is a policy debate within the administration and the Congress on how to balance competing economic and foreign policy interests with concerns over technology transfer—issues that resonate particularly with respect to China.

Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×

Table 5.1 Launch Capacity to EOS Orbit, Cost, and Performance History of Candidate Small Satellite Launch Vehicles

Vehicle/Configuration

Capacity to 700 km Sun-Synchronous Orbit (kg)

Cost ($M)

Performance History (Successes/Flights through Oct. 1988)

U.S. LAUNCH VEHICLES

Delta II 7920/25

3,275

50

47/49

Delta II 7320

1,750

35

0/0

Pegasus XL

225

14

18a/23b

Taurus XL/Orion 38

945

24

0/0

Taurus/Orion 38

860

22

3/3

Athena 3

2,200

30

0/0

Athena 2

700

22

1/1

Athena 1

200

16

1/2

Conestoga 1229

220

12

0/0

Conestoga 1620

540

18

0/1

FOREIGN LAUNCH VEHICLES

CZ-2D (China)

1,200

20

5/5

PSLV Mk2 (India)

1,300

12/15

1/1

Molniya M (Russia)

1,775

30

256/289

Shavit 2c (Israel/US)

340

15

0/0

Shtil 1N (Russia)

185

5/6

1/1

Tsyklon 3 (Ukraine)

2,300

25

111/117

a Successes exclude incorrect orbit, failure to separate on orbit, and damaged spacecraft.

b Includes all versions of the Pegasus.

c Coleman Research Corporation, in collaboration with Israel Aircraft Industries, has recently won a Small Expendable Launch Vehicle contract from the National Aeronautics and Space Administration to provide launch services in the United States using an export version of the Israeli-designed Shavit rocket (Next). The Shavit is a solid-fuel rocket with performance comparable to the Pegasus XL. Through January 1998, it had achieved three successful launches in five attempts.

SOURCE: International Space Industry Report, Nov. 9, 1998; available online at <CS:WebLink>http://www.launchspace.com/isir/home.html>.

Table 5.2 Launch Vehicle Fairing Dimensions and Launch Environment

 

Pegasus XL

Athena 1 (Mod 92 fairing

Taurus (63 in fairing

Conestoga (1229 fairings)

Delta II (7920 (9.5 ft fairing)

Fairing dimensions

Max diameter (m)

1.118

1.981

1.372

1.616

<2.54

Max cylinder length (m)

1.110

2.291

2.692

0.392–2.664

3.81

Max cone length (m)

1.016

2.002

1.270

1.768

1.94

Launch environment

Axial accel (g)

<13.0

<+4/-8

<11.0

<11.0

<6.0

Lateral accel (g)

< ±6.0

< ±2.5

NA

< ±2.7

< ±2.0

Acoustic (dB)

<141

<133.5

<141

<128.5

<139.6

Longitudinal freq (Hz)

NA

>15

NA

NA

>35

Lateral freq (Hz)

NA

>30

NA

NA

>15

NA = not applicable.

Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×

Figure 5.1

Launch vehicle cost per unit mass to EOS orbit.

SUMMARY

Achieving the full promise of small satellites will require the availability of reliable U.S. launch vehicles with a full range of performance capabilities. This is currently not the case: There is a significant gap in capability between the Pegasus/Athena/Taurus launch vehicles and the Delta II. Plans to fill this gap by numerous suppliers are encouraging, as are the efforts by launch vehicle suppliers to provide a range of fairing sizes to accommodate a larger percentage of potential missions. Foreign launch vehicles may also ultimately play a role in filling this gap, should U.S. policy change.

Early experience with the new small launch vehicles has included a number of failures—probably due in part to a desire to minimize development costs for these commercial ventures. Continued development should overcome the difficulties and yield a suitable balance between cost and reliability. However, it will take some time—and, likely, some additional failures—before any of these launch vehicles establish a reliability record approaching that of the Delta II.

Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×
Page 37
Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×
Page 38
Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×
Page 39
Suggested Citation:"5 Small Launch Vehicles." National Research Council. 2000. The Role of Small Satellites in NASA and NOAA Earth Observation Programs. Washington, DC: The National Academies Press. doi: 10.17226/9819.
×
Page 40
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The Role of Small Satellites in NASA and NOAA Earth Observation Programs Get This Book
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Remote observations of Earth from space serve an extraordinarily broad range of purposes, resulting in extraordinary demands on those at the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and elsewhere who must decide how to execute them. In research, Earth observations promise large volumes of data to a variety of disciplines with differing needs for measurement type, simultaneity, continuity, and long-term instrument stability. Operational needs, such as weather forecasting, add a distinct set of requirements for continual and highly reliable monitoring of global conditions.

The Role of Small Satelites in NASA and NOAA Earth Observation Porgrams confronts these diverse requirements and assesses how they might be met by small satellites. In the past, the preferred architecture for most NASA and NOAA missions was a single large spacecraft platform containing a sophisticated suite of instruments. But the recognition in other areas of space research that cost-effectiveness, flexibility, and robustness may be enhanced by using small spacecraft has raised questions about this philosophy of Earth observation. For example, NASA has already abandoned its original plan for a follow-on series of major platforms in its Earth Observing System.

This study finds that small spacecraft can play an important role in Earth observation programs, providing to this field some of the expected benefits that are normally associated with such programs, such as rapid development and lower individual mission cost. It also identifies some of the programmatic and technical challenges associated with a mission composed of small spacecraft, as well as reasons why more traditional, larger platforms might still be preferred. The reasonable conclusion is that a systems-level examination is required to determine the optimum architecture for a given scientific and/or operational objective. The implied new challenge is for NASA and NOAA to find intra- and interagency planning mechanisms that can achieve the most appropriate and cost-effective balance among their various requirements.

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