The Passive Voice

Question

I have stumbled upon this sentence:

Etwa zwei Kilometer überm Boden wird der Fallschirm abgeworfen und Landetriebwerke zünden.

I am not learning German for that long and so I got a little confused here. The paragraph is talking about something in the future, but I know that when it is clear we are talking about the future, we can use the present tense. So I thought the verb is in the passive voice. But then there is the "zünden", which is infinitive, not Partizip II.

Could someone please explain to me, why is it the way it is? The paragraph is then filled with "werden + Partizip II" (or is it maybe adjective?), so this really threw me off and I cannot stop thinking about it. Here is how the text continues:

In 20 Metern Höhe wird der „Sky Crane“ aktiviert: Der Rover klappt seine sechs Räder aus und wird an Nylonseilen vom schwebenden „Himmelskran“ herabgelassen. (no more infinitive)

The same thing happens in the text one more time:

21:42 Uhr wird sich der Überschall-Fallschirm entfalten und der Hitzeschutzschild abgeworfen. ("wird ... entfalten").

Answer 1

These are actually two main sentences connected by "und", with different subjects and predicates. A comma before und would probably have clarified it for you. It should be:

Etwa zwei Kilometer überm Boden wird der Fallschirm abgeworfen, und Landetriebwerke zünden.

The first sentence:

Etwa zwei Kilometer überm Boden wird der Fallschirm abgeworfen.

is just your standard passive voice in present tense. The second part:

Landetriebwerke zünden.

is a very short but full sentence in active voice. The article for "Landetriebwerke" is missing because it's an indefinite plural, i.e. the same sentence in singular would be:

Ein Landetriebwerk zündet.

The following sentences you cite are partly in active, partly in passive voice, and at the end you even have a sentence in future tense. Some silent reuse of words makes these sentences a bit harder to understand. I'm splitting them up into sentences here, one sentence per line:

In 20 Metern Höhe wird der „Sky Crane“ aktiviert. (passive voice)
Der Rover klappt seine sechs Räder aus ... (active voice)
... und [der Rover] wird an Nylonseilen vom schwebenden „Himmelskran“ herabgelassen. (passive voice)
Um 21:42 Uhr wird sich der Überschall-Fallschirm entfalten ... (active voice, future tense)
... und der Hitzeschutzschild [wird] abgeworfen. (passive voice).

Note how the second part of the last sentence reuses the verb "wird". It is originally used for future tense in the first part, and then it is reused as the implied modal verb for passive voice in the second part.

Answer 2

While the sentence describes a future event, it is grammatically written in Präsens (present tense). This is called futurisches Präsens, see e. g. grammis. To quote the essence:

[...] verdient besondere Beachtung, denn, anders als die traditionelle Bezeichnung suggeriert, wird im Deutschen meist Präsens und nicht etwa das Futur verwendet, wenn von Zukünftigem die Rede ist.

(Contrary to the traditional name, German mostly uses present tense when describing future events.)

The passive form is built using Partizip II which adds an irritating appearance of past. You may want to read more about Vorgangspassiv.

Answer 3

One potentially helpful strategy for identifying passive constructions does not rely on verb forms. While it is the case the prototypical passive consists of a form of werden combined with a past participle and can therefore be recognised as such just by examining the forms, there are some verbs where the past participle is identical to the infinitive:

1. werden + infinitive, active:

   Man_x wird diese Helden_y schnell wieder vergessen.
   Eine Antenne_x wird die Signale_y empfangen.

2. werden + past participle, passive:

   Diese Helden_y werden schnell wieder vergessen.
   Die Signale_y werden von einer Antenne_x empfangen.

What allows these sentences to be interpreted unambiguously is knowledge about what complements a verb takes and what semantic roles x, y, … these complements fill. For instance, vergessen and empfangen are transitive verbs: They take a subject and an accusative object, with the object expressing what is being forgotten or received (the role indicated by y) and the subject expressing who is doing the forgetting or receiving (the role indicated by x).

The sentences under 1. are congruent with these expectations. However, those under 2. show a divergence: There is no object, and the subject expresses what is being forgotten or received (the role indicated by y, expressed by an object in the sentences under 1.). The role x is unspecified in one case and specified by an adverbial governed by von in the other.

It is therefore possible to identify a passive without looking at verb forms at all, just going by what complements there are and semantic role they are linked with. This strategy comes in handy for interpreting the many constructions that behave similarly to a passive:

• Ein solches Unglück_y lässt sich nicht leicht vergessen.

• Die Signale_y waren kaum zu empfangen.

• Die Signale_y waren kaum empfangbar.

• die von der Antenne_x empfangenen Signale_y

• Wir haben das Gebäude_y von Experten_x vermessen lassen.

In all these constructions, the subject fills the same semantic role y as the object of a corresponding active clause. (The last example is slightly more difficult, as the subject of vermessen is realised as the accusative object of lassen.)

This strategy can be applied to your examples. For instance:

(1) 21:42 Uhr wird sich_y der Überschall-Fallschirm_x entfalten und (2) der Hitzeschutzschild_y [wird] abgeworfen.

The first sentence must be active since the subject is doing the unfurling and the object is being unfurled (even if subject and object, the verb being used reflexively, in this instance denote the same thing; if this problematic, think die Sonde wird den Schirm entfalten instead). The second sentence must be passive since there is no object and Hitzeschutzschild has the role y, i.e. is what is being discarded, not x, i.e. what is doing the discarding.

Answer 4

Good explanations already for the grammatical structure, but no explanations for why the writer might have chosen this combination.

I'd remark that the example can actually be translated quite directly to English:

About two kilometres above ground, the parachute is jettisoned and landing engines ignite.

Like in the German version, you have “the parachute is jettisoned” in passive voice, and then “the landing engines ignite” in active voice.

It could be changed to have both in active form:

Etwa zwei Kilometer überm Boden wirft der Lander den Fallschirm ab und Landetriebwerke zünden.

About two kilometres above ground, the lander jettisons its parachute and landing engines ignite.

...which is a bit more awkward, because you need an extra subject.

It could also be changed with both passive

Etwa zwei Kilometer überm Boden wird der Fallschirm abgeworfen und Landetriebwerke werden gezündet.

About two kilometres above ground, the parachute is jettisoned and landing engines are ignited.

The problem here is that the parachute is singular but the engines plural. That's why two different forms of “werden” are needed.

If both were singular or both plural, you could group them together:

Etwa zwei Kilometer überm Boden wird der Fallschirm abgeworfen und das Landetriebwerk gezündet.

Etwa zwei Kilometer überm Boden werden die Fallschirme abgeworfen und die Landetriebwerke gezündet.

Only, in this case it's actually just one parachute but multiple engines. That is probably the reason why the ignition-part is phrased in active voice, to avoid the second “werden” this way.