A new measurement of the chromospheric emission line λ 10830

less steel 0.003 and 0.006 inch thick, and copper wire 0.002 and 0.003 inch in diameter. Several h u n d r e d micrometeoroid impacts were measured by the impact detectors during the useful life of the Explorer X I I I ; however, no p e n e t r a t i o n s were recorded in a n y of the m a t e r i a l samples. The satellite instrum e n t a t i o n performed as expected with the exception of t h e cadmium-sulfide cell detector which became inoperative during ascent. T e m p e r a t u r e s measured on the satellite at various locations were generally higher t h a n predicted which, as shown b y the post-flight analysis, could be explained by aerodynamic heating during the low-perigee passages. This report includes a description of the spacecraft, experiments, and l a u n c h vehicle, as well as a discussion of flight d a t a during ascent to orbit, orbital performance, and d a t a acquisition and reduction. Telemeter and power supply systems are given extensive coverage and operational results are presented. The d~ermal design is discussed and actual thermal-performance d a t a in flight are presented. A section is devoted to subsystem, flight qualification, and flight-acceptance testing. Separate sections describe the aim and results of the experiments, discuss the design, development, c o n s t r u c t i o n and performance of the a p p a r a t u s used. Sections II and V are devoted to solar energy power systems.

X I - - R a d i a t i o n Mechanics and Availability: Insolation, Spectroscopy and Spectral Distribution

House, L. L., and D. E. Billings, High Altitude Observatory, Boulder, Colo., "Time-Dependent Coronal Ionization", Reprint, The Astrophysical J1, 140, No. 3, October, 1964, 10 p. T i m e - d e p e n d e n t ionization processes are tested for possible significance u n d e r the conditions of a shock wave passing t h r o u g h the corona. E q u a t i o n s are solved to determine the time v a r i a t i o n of ion and electron temperatures. The resulting electron t e m p e r a t u r e is used to compute the time v a r i a t i o n in ionization of iron. The results of these calculations, when compared to observational characteristics of the corona, definitely favor processes in the corona comparable in scale and frequency to those in the photosphere.

House, Lewis L., William A. Deutsehman and George A. Sawyer, High Altitude Observatory, Boulder, Colo., and Los Alamos Scientific Lab., N. M., "Comparison of Solar and Laboratory Iron Spectra in the Vacuum Ultraviolet", Reprint, Astrophysical J, 1~0, No. 2, August 15, 1964, 4 p. The solar s p e c t r u m in the extreme ultraviolet, as observed by Hinteregger (19(i3), Behring, N e u p e r t , and Lindsay (1962), and Tousey, Austin, Purcell, a n d Widing (1962), contains m a n y unidentified lines. A group of lines in the range 150-220 _~ region are especially strong. I n the extreme u l t r a v i o l e t t h e i r s t r e n g t h is second only to the He I I 304 ,~. Recent observations of the Zeta s p e c t r u m (Fawcett, Gabriel, Griffin, Jones, and Wilson, 1963) have shown a coincidence between several of the strong solar lines and l a b o r a t o r y lines. M a n y of the lines are p r e s u m a b l y iron because the plasma is contained in a stainlesssteel discharge tube. The preliminary work reported in this p a p e r gives f u r t h e r evidence as to the n a t u r e of these lines. The technique the authors use to excite and observe the spectra of highly ionized atonls has been described previously (House and Sawyer, 1964). Briefly stated, the m e t h o d is to add impurities to a high energy t h e t a - p i n c h , Scylla I I I (Los Alamos), and observe the time i n t e g r a t e d spectra p h o t o g r a p h i c a l l y with a 2-m grazing incidence rocket spectrograph. The spectra w i t h and w i t h o u t impurities are compared to show the presence of new lines. In the Scylla device the discharge is contained in a ceramic tube, which therefore offers the possibility of indep e n d e n t l y introducing iron to the plasma. Fig. 1 shows tracings of spectra in the 150-220-~ region.

Vol. 10, No. 1, I966

Buehele, Donald R., Lewis Research Center, Clevehmd, Ohio, "Nonlinear-Averaging Errors in Radiation Pyrometry", NASA TN D-2406, August, 1964, 16 p., illus. The error in measuring the average of a fluctuating temperature b y optical means is determined for cases of temporal or spatial fluctuation with small optical depth. The m e t h o d is applicable to line-reversal, absorption-emission, and other pyrometric methods t h a t involve the m e a s u r e m e n t of the absolute or relative magnitudes of r a d i a n t flux. I t is also applicable to some techniques of gas analysis by radiometric means. Experim e n t a l confirmation of the analysis is described for a Gaussian p r o b a b i l i t y density distribution.

Warwick, Jmnes W., and George A. Dulk, High Altitude Observatory Lab, Boulder, Colorado, "I:araday Rotation on Decametric Radio Emissions from Jupiter", Reprint, S~ience, 145, No. 3(i30, July 1964, 4p. Some decametric radio emissions from J u p i t e r observed recently exhibit, effects which are a t t r i b u t a b l e to F a r a d a y rotation within the e a r t h ' s ionosphere. This report presents the evidence for the presence of F a r a d a y r o t a t i o n and discusses its origin. Identification of the inagnetoionic mode in which the emission is generated at J u p i t e r appears possible, a l t h o u g h near the limit of accuracy of our present observations. The emission seems to be generated in the e x t r a o r d i n a r y mode.

Athay, R. Grant, High Altitude Observatory Lab, Boulder, Colorado, "The Challenge of Chromospheric Physics", Reprint, Science, 1/~3, No. 3611, Mar~h, 1964, 11 p. illus. Chromospheric plasma reveals complex i n t e r a c t i o n of magnetic, h y d r o d y n a m i c , r a d i a t i v e and t h e r m a l fields.

Fisher, Richard Royal, High Altitude Observatory Lab, Boulder, Colo., "A New Measurement of the Chromospheric Emission Line X 10830", Reprint, Notes, The Astrophysical J1, October 1964, 3 p. For a period of years it has been possible to observe the infrared line X 10830 of He I in the solar atmosphere. This line was first identified in the F r a u n h o f e r s p e c t r u m in 1934 b y H. D. and H. W. Babcock, a n d has been observed b o t h on the disk and a t the limb at various times since t h e n (L. and M. d ' A z a m b u j a 1938, 1940; Mohler and Goldberg 1956). At the High Altitude Observation s t a t i o n at Climax, Colorado, observations were first made with infrared sensitive film (TandbergHanssen, Curtis, a n d W a t s o n 1959; T a n d b e r g Hanssen 1960), b u t recently image-tube observations have superseded these (Firor and Zirin 1962). In the case of the observations discussed in this paper, an [ T T FW-132 image tube with a n S-1 photocathode was used.

Athay, R. Grant, and R. J. Bessey, High Altitude Observatory, Boulder, Colo., "Doppler Shifts and Line Broadening in Spicules", Reprint, The Astrophysical Jl, 140, No. 3, October 1, 19~4, 7 p. Doppler shifts measured for solar spicules in Ha, Da, and H (Ca II) suggest t h a t the anomalously broad lines of Ca II (Athay 1961) are due, in part, to i n a d e q u a t e spatial resolution as suggested b y Zirker (1962), b u t t h a t this is not the prinlary cause of the anomalous broadening. Ha a n d H and K spicules are found to have p r e d o m i n a n t l y wide profiles at low and intermediate heights, but at great heights the profile widths for most of the few remaining features are only a b o u t one t h i r d as wide as at lower heights. I t appears t h a t this results mainly, however, from the fact t h a t the features w i t h narrow profiles are intrinsically b r i g h t e r at great heights t h a n are the features 59